Emboli protection devices and related methods of use

ABSTRACT

An evacuation sheath assembly and method of treating occluded vessels which reduces the risk of distal embolization during vascular interventions is provided. The evacuation sheath assembly includes an elongated tube defining an evacuation lumen having proximal and distal ends. A proximal sealing surface is provided on a proximal portion of the tube and is configured to form a seal with a lumen of a guided catheter. A distal sealing surface is provided on a distal portion of the tube and is configured to form a seal with a blood vessel. Obturator assemblies and infusion catheter assemblies are provided to be used with the evacuation sheath assembly. A method of treatment of a blood vessel using the evacuation sheath assembly includes advancing the evacuation sheath assembly into the blood vessel through a guide catheter. Normal antegrade blood flow in the blood vessel proximate to the stenosis is stopped and the stenosis is treated. Retrograde blood flow is induced within the blood vessel to carry embolic material dislodged during treating into the evacuation sheath assembly. If necessary to increase retrograde flow, the coronary sinus may be at least partially occluded. Alternatively, antegrade flow may be permitted while flow is occluded at the treatment site.

DESCRIPTION OF THE INVENTION

[0001] This application is a continuation-in-part of application Ser.No. 09/940,986, filed Aug. 29, 2001, which is a continuation-in-part ofapplication Ser. No. 09/845,162, filed May 1, 2001, both of which areincorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to apparatus and methods used toprevent the introduction of emboli into the bloodstream during and aftersurgery performed to reduce or remove blockage in blood vessels.

BACKGROUND OF THE INVENTION

[0003] Narrowing or occlusion of blood vessels, such as the walls of anartery, inhibit normal blood flow. Such blockages, whether partial orfull, can have serious medical consequences, depending upon theirlocation within a patient's vascular system. Narrowing or blockage ofthe coronary vessels that supply blood to the heart, a condition knownas atherosclerosis, may cause damage to the heart. Heart attacks(myocardial infarction) may also result from this condition. Othervessels are also prone to narrowing, including carotids, renals,cerebrals, and other peripheral arteries.

[0004] Various surgical procedures are currently used to reduce orremove the blockage in blood vessels. Such procedures include balloonangioplasty, which involves inserting a balloon catheter into thenarrowed or occluded area, expanding the balloon in the narrow oroccluded area, and if necessary, placing a stent in the now expandedarea to keep it open. Another common procedure used is atherectomy wherethe lesion is cut away and removed from the vessel, or abrasivelyground, sending the small particulates downstream. Other endovascularprocedures make use of thrombectomy, drug delivery, radiation,stent-grafts, and various diagnostic devices.

[0005] Another alternative is bypass surgery in which a section of veinis removed from, for example, the patient's leg, e.g., a saphenous vein,to be used as a graft to form a pathway to bypass the occluded area. Thesaphenous vein graft (SVG), however, is also susceptible to becomingoccluded in a manner similar to that of the bypassed vessel. In such acase, angioplasty (with or without the use of a stent) or atherectomy isoften used on the SVG to remove or reduce the blockage.

[0006] Each of the above described procedures carries with it the riskthat some of the treated plaque will be disrupted, resulting in embolicparticulates released in the bloodstream. These emboli, if allowed toflow through the vascular system, may cause subsequent infarctions orischemia in the patient. SVGs treated by angioplasty or atherectomycarry a particularly high risk of this result, but such problems arealso encountered in the other types of procedures mentioned, such ascarotids, or native coronary arteries, particularly those whose lesionsinclude thrombus.

[0007] Several systems to prevent emboli being released into thebloodstream during such procedures have been tried. One system uses aballoon to totally occlude the artery distal (downstream) to the area ofblockage to be treated. In this system, a guidewire with a balloon isintroduced into the narrowed or occluded area, and passes through thenarrowed or occluded area to a position downstream of the blockage. Theballoon is inflated, the blockage is reduced or removed, and then theblood proximal to the balloon is withdrawn from the blood vessel toremove any particles or emboli which have resulted from the reduction ofthe blockage. While this system has shown a decrease in emboli relatedcomplications in patients undergoing such treatments, the event rateremains significant. One particular problem with this system is passingthe guidewire and balloon through the narrowed or occluded area prior toocclusion with the balloon, creating the risk that emboli will beproduced as the balloon passes through the blockage. Thus, anyparticulate or plaque disturbed during this passage which forms emboliprior to inflation of the balloon is free to flow through the vascularsystem, increasing the risk for infarction or ischemia. Also, any debrisor particulate matter which gathers around the edges of the balloon mayslip downstream during deflation and retrieval of the balloon. Inaddition, this system requires that blood flow be totally occluded inthe vessel for relatively prolonged intervals that may induce adversecardiac events. Although this may not be a problem clinically, manypatients perceive the occlusion of blood flow for this period of time asproblematic.

[0008] Another system used to prevent emboli being released into thebloodstream during surgical intervention is a filter. As with theocclusion balloon, the filter must pass through the narrowed or occludedarea and is deployed distal (downstream) to the blockage. The filterthen catches any particulate material generated during the removal ofthe blockage. The filter offers the benefit that blood flow is nottotally occluded. However, because the filter must pass through theblockage, it suffers from the same drawback as the previous system—riskof the creation of emboli during passage of the filter through theblockage. In addition, it is difficult to deploy the filter securelyagainst the walls of the vessel to prevent flow around the filter andany debris or particulate matter which gathers around the edges of thefilter may slip downstream during its retrieval. Also, in order to allowblood flow during the procedure, the pores of the filter should be atleast 100 microns in diameter. The majority of emboli have a diameterbetween about 40 microns and about 100 microns. Thus, the filter willnot catch the majority of emboli, which may flow downstream and cause ainfarction or ischemia. The filter also cannot prevent the passage ofcertain neurohumoral or vasoactive substances which are released intothe blood during the procedure and may contribute to generalizedvasospasm of the distal coronary tree.

[0009] Thus, there is a need for an improved system and method oftreating occluded vessels which can reduce the risk of distalembolization during vascular interventions. There is also a need for asystem which reduces the amount of time that total occlusion of theblood flow is necessary.

SUMMARY OF THE INVENTION

[0010] In accordance with the invention, methods and apparatuses forreducing or removing a blockage within a vessel without permittingembolization of particulate matter are provided. The methods andapparatuses occlude blood flow for a minimal amount of time and captureparticulate matter created during each step of the surgical process.

[0011] According to one aspect of the invention, the finalized claimswill be summarized here.

[0012] Additional objects and advantages of the invention will be setforth in part in the description which follows, and in part will beobvious from the description, or may be learned by practice of theinvention. The objects and advantages of the invention will be realizedand attained by means of the elements and combinations particularlypointed out in the appended claims.

[0013] It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory only and are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings, which are incorporated in andconstitute a part of this specification, illustrate several embodimentsof the invention and together with the description, serve to explain theprinciples of the invention. In the drawings,

[0015]FIG. 1A is a cross-sectional side view of a partial lengthevacuation sheath according to one embodiment of the present invention;

[0016]FIG. 1B is a cross-sectional view of the partial length evacuationsheath taken along line 1B-1B of FIG. 1A;

[0017]FIG. 1C is a cross-sectional side view of an alternativeembodiment of a partial length evacuation sheath according to oneembodiment of the present invention;

[0018]FIG. 1D is a cross-sectional view of the partial length evacuationsheath taken along line 1D-1D of FIG. 1C;

[0019]FIG. 2A is a cross-sectional side view of an expandable evacuationsheath, shown in an unexpanded state, according to another embodiment ofthe present invention;

[0020]FIG. 2B is a cross-sectional view of the unexpanded expandableevacuation sheath taken along line 2B-2B of FIG. 2A;

[0021]FIG. 2C is a cross-sectional side view of the expandableevacuation sheath of FIG. 2A in an expanded state;

[0022]FIG. 2D is a cross-sectional view of the expanded expandableevacuation sheath taken along line 2D-2D of FIG. 2C;

[0023]FIG. 2E is a cross-sectional view of the expanded evacuationsheath taken a long line 2E-2E of FIG. 2C.

[0024]FIG. 3A is cross-sectional side view of a full-length evacuationsheath according to another embodiment of the present invention;.

[0025]FIG. 3B is cross-sectional view of the full-length evacuationsheath taken along line 3B-3B of FIG. 3A;

[0026]FIG. 4A is cross-sectional side view of a guidingcatheter/evacuation sheath combination according to yet anotherembodiment of the present invention;

[0027]FIG. 4B is cross-sectional view of the guiding catheter/evacuationsheath combination taken along line 4B-4B of FIG. 4A;

[0028]FIG. 5A is cross-sectional view of the partial evacuation sheathof FIGS. 1A and 1B deployed within a vessel;

[0029]FIG. 5B is cross-sectional view of the expandable evacuationsheath of FIGS. 2A-2D deployed within a vessel;

[0030]FIG. 5C is cross-sectional view of the full-length evacuationsheath of FIGS. 3A and 3B deployed within a vessel;

[0031]FIG. 5D is cross-sectional view of the guiding catheter/evacuationsheath combination of FIGS. 4A and 4B deployed within a vessel;

[0032] FIGS. 6A-6I are cross-sectional views of the partial lengthevacuation sheath of FIGS. 1A and 1B as employed in a method accordingto one aspect of the present invention;

[0033] FIGS. 7A-7I are cross-sectional views of the expandableevacuation sheath of FIGS. 2A-2D as employed in a method according toanother aspect of the present invention;

[0034] FIGS. 8A-8I are cross-sectional views of the full-lengthevacuation sheath of FIGS. 3A and 3B as employed in a method accordingto a further aspect of the present invention;

[0035] FIGS. 9A-9H are cross-sectional views of the guidingcatheter/evacuation sheath of FIGS. 4A and 4B as employed in a methodaccording to yet another aspect of the present invention;

[0036]FIG. 10A is a cross-sectional side view of another embodiment ofan evacuation sheath assembly enclosed in a delivery sheath and beingdelivered through a guiding catheter;

[0037]FIG. 10B is a cross-sectional side view of a braided sheathforming an evacuation head of the evacuation sheath assembly of FIG. 10Ain an unexpanded state with the delivery sheath removed;

[0038]FIG. 10C is a cross-sectional side view of the braided sheath ofFIG. 10B in the expanded state; and

[0039]FIG. 10D is cross-sectional view of the guiding/evacuation lumenof the evacuation sheath assembly of FIGS. 1A-10C deployed within ablood vessel.

[0040]FIG. 11A is a cross-sectional side view of a partial lengthevacuation sheath according to one embodiment of the present invention;

[0041]FIG. 11B is a cross-sectional view of the partial lengthevacuation sheath taken along line A-A of FIG. 11A;

[0042]FIG. 11C is a cross-sectional side view of a partial lengthevacuation sheath according to one embodiment of the present invention;

[0043]FIG. 11D is a cross-sectional view of the partial lengthevacuation sheath taken along line A-A of FIG. 11C;

[0044]FIG. 11E is a cross-sectional side view of a partial lengthobturator according to one embodiment of the present invention;

[0045]FIG. 11F is a cross-sectional view of the partial length obturatortaken along line A-A of FIG. 11E;

[0046]FIG. 11G is a cross-sectional side view of the partial lengthobturator located within a partial length evacuation sheath;

[0047]FIG. 11H is a cross-sectional side view of partial length balloonobturator according to one embodiment of the present invention;

[0048]FIG. 11I is a cross-sectional view of the partial length balloonobturator taken along line A-A of FIG. 11H;

[0049]FIG. 11J is a cross-sectional view of the partial length balloonobturator taken along line B-B of FIG. 11H;

[0050]FIG. 11K is a cross-sectional side view of the partial lengthballoon obturator located within a partial length evacuation sheath;

[0051]FIG. 12A is a cross-sectional side view of an infusion catheteraccording to one embodiment of the present invention;

[0052]FIG. 12B is a cross-sectional view of the infusion catheter takenalong line A-A of FIG. 12A;

[0053]FIG. 12C is a cross-sectional view of the infusion catheter takenalong line B-B of FIG. 12A;

[0054]FIG. 12D is a cross-sectional side view of an infusion catheteraccording to one embodiment of the present invention;

[0055]FIG. 12E is a cross-sectional view of the infusion catheter takenalong line A-A of FIG. 12D;

[0056]FIG. 12F is a cross-sectional view of the infusion catheter takenalong line B-B of FIG. 12D;

[0057]FIG. 12G is a cross-sectional side view of an alternative infusioncatheter according to one embodiment of the present invention;

[0058]FIG. 12H is a cross-sectional view of the infusion catheter takenalong line A-A of FIG. 12G;

[0059]FIG. 12I is a cross-sectional side view of another infusioncatheter according to one embodiment of the present invention;

[0060]FIG. 12J is a cross-sectional view of the infusion catheter takenalong line A-A of FIG. 12I;

[0061]FIG. 12K is a cross-sectional side view of an infusion catheteraccording to one embodiment of the present invention;

[0062]FIG. 12L is a cross-sectional view of the infusion catheter takenalong line A-A of FIG. 12K;

[0063]FIG. 12M is a cross-sectional side view of an infusion catheteraccording to one embodiment of the present invention;

[0064]FIG. 12N is a cross-sectional view of the infusion catheter takenalong line A-A of FIG. 12M;

[0065]FIG. 13 is a cross-sectional view of the partial length evacuationsheath of FIGS. 11A and 11B deployed in a blood vessel according to afurther aspect of the present invention;

[0066]FIG. 14 is a cross-sectional view of the partial length evacuationsheath of FIGS. 11A and 11B and the over the wire infusion sheath ofFIGS. 12K and 12L deployed in a blood vessel according to a furtheraspect of the present invention;

[0067]FIG. 15 is a cross-sectional view of a heart with a coronary sinuspartially occluded by an occlusion catheter according to one aspect ofthe present invention;

[0068]FIG. 16A is side view of a full-length evacuation sheath assemblyaccording to another embodiment of the present invention;

[0069]FIG. 16B is a cross-sectional side view of the evacuation sheathassembly of FIG. 16A;

[0070]FIG. 16C is an enlarged cross-sectional side view of a portion ofthe intermediate shaft portion of the evacuation sheath assembly incircle “C” of FIG. 16B;

[0071]FIG. 16D is an enlarged cross-sectional side view of the proximalend of the evacuation sheath portion of the evacuation sheath assemblyin circle “D” of FIG. 16B;

[0072]FIG. 16E is a cross-sectional view of the evacuation sheathassembly taken along line E-E of FIG. 16B;

[0073]FIG. 16F is a cross-sectional side view of a distal end portion ofthe evacuation sheath portion of the evacuation sheath assembly of FIG.16B;

[0074]FIG. 16G is a cross-sectional side view of an alternativeembodiment of a distal end portion of the evacuation sheath portion ofthe evacuation sheath assembly of FIG. 16B;

[0075]FIG. 16H is an isometric sectional view of a marker portion andinflation lumen port of the evacuation sheath assembly of FIG. 16A;

[0076]FIG. 16I is a side view of an arrangement with the evacuationsheath assembly of FIG. 16A in use with a guide catheter;

[0077]FIG. 16J is an isometric view of a support collar used in theevacuation sheath assembly of FIG. 16A;

[0078]FIG. 17A is a cross-sectional side view of an infusion catheteraccording to another embodiment of the present invention;

[0079]FIG. 17B is a cross-sectional view of the infusion catheter takenalong line B-B of FIG. 17A;

[0080]FIG. 17C is a cross-sectional view of the infusion catheter takenalong line C-C of FIG. 17A; and

[0081]FIG. 17D is a cross-sectional view of the infusion catheter takenalong line D-D of FIG. 17A.

DESCRIPTION OF THE EMBODIMENTS

[0082] Reference will now be made in detail to the present embodimentsof the invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

[0083] The present invention provides a system and method for evacuatingemboli, particulate matter, and other debris from a blood vessel, andparticularly from an occluded blood vessel. As used herein, an“occlusion,” “blockage,” or “stenosis” refers to both complete andpartial blockages of the vessels, stenoses, emboli, thrombi, plaque,debris and any other particulate matter which at least partiallyoccludes the lumen of the blood vessel.

[0084] Additionally, as used herein, “proximal” refers to the portion ofthe apparatus closest to the end which remains outside the patient'sbody, and “distal” refers to the portion closest to the end insertedinto the patient's body.

[0085] This method and apparatus are particularly suited to be used indiseased blood vessels that have particularly fragile lesions, orvessels whereby the consequences of even small numbers of small embolimay be clinically significant. Such blood vessels include diseased SVGs,carotid arteries, coronary arteries with thrombus, and renal arteries.However, it is contemplated that the method and apparatus can be adaptedto be used in other areas, such as other blood vessels.

[0086] As embodied herein and shown in FIG. 1A, an evacuation sheathassembly 100 is provided. Evacuation sheath assembly 100 includes anevacuation head and a shaft. As embodied herein and shown in FIG. 5A,the evacuation sheath assembly 100 is sized to fit inside a guidecatheter to advance a distal end of the evacuation sheath assembly intoa blood vessel to treat a stenosis.

[0087] Although described herein with respect to coronary arteryintervention, it is contemplated that evacuation sheath assembly 100 maybe suitable for use in other surgical procedures in other vessels, wherereduction or removal of a blockage in a blood vessel is beneficial.Additionally, although the method of use of the evacuation sheathassembly will be described with respect to placing a stent within avessel, the evacuation sheath assembly 100 can be used during othertherapies, such as angioplasty, atherectomy, thrombectomy, drugdelivery, radiation, and diagnostic procedures.

[0088] As shown in FIG. 1A, an evacuation head 132 is provided.Evacuation head 132 includes a multi-lumen tube 138. The multi-lumentube 138 is preferably made of a relatively flexible polymer such aslow-density polyethylene, polyurethane, or low durometer Pebax®material. Alternatively, the multi-lumen tube 138 can be made of acomposite polymer and metal material or from other suitablebiocompatible materials exhibiting appropriate flexibility, for example.The multi-lumen tube 138 preferably includes first and second lumens.The first and preferably larger of the lumens, an evacuation lumen 140,is designed to allow for the passage of interventional devices such as,but not limited to, stent delivery systems and angioplasty catheters.The evacuation lumen 140 is also designed to allow for fluid flow, suchas blood, blood/solid mixtures, radiographic dye and saline, within theevacuation lumen 140. This flow of fluid may occur regardless of whetheran interventional device is within the evacuation lumen 140. Theproximal and distal ends 140 a, 140 b of the evacuation lumen 140 arepreferably angled to allow for smoother passage of the evacuation sheathassembly 100 through a guide catheter, and into a blood vessel, and tofacilitate smoother passage of other therapeutic devices through theevacuation lumen 140 of the evacuation head 132. The larger area of theangled open ends also allows for larger deformable particulate matter topass through the lumen more smoothly.

[0089] The second and preferably smaller lumen of the multi-lumen tube138 is an inflation lumen 142 (having an open proximal end 142 a and aclosed distal end 142 b) designed to provide fluid to inflate balloonson the evacuation head 132. The fluid may be either gas or liquid inform.

[0090] An alternative construction of the multi-lumen tube 138 of theevacuation head 132 is shown in FIG. 1C. Depending on the tortuosity ofthe curves of the guide catheter and the blood vessel through which theevacuation head 132 is to be advanced, it may be desirable toincorporate a kink resisting structure. As embodied herein and shown inFIG. 1C, the multi-lumen tube 138 may be formed around a coil 139 suchthat the coil 139 is embedded within the multi-lumen tube 138.Alternatively, coil 139 may be positioned on the inside surface definingthe evacuation lumen 140. The coil 139 can be “wound-down” initially,then re-expanded to make contact with the inner surface of evacuationlumen 140. A covering of polyurethane can then be applied to contain thecoil 139, and secure it in position within evacuation lumen 140. Thepolyurethane may be applied by a solvent casting of polyurethane in anappropriate solvent. Alternatively, the structure may be formed bycoextruding the shaft tube together with a coil or braid or by othersuitable means. A further alternative may include positioning the coilon the outer surface of the multi-lumen tube 138.

[0091] An alternative construction of the multi-lumen tube 138 of theevacuation head 132 is shown in FIG. 11A and incorporates akink-resisting structure. A coil 139 can be wound directly onto themulti-lumen tube or expanded from a wound state and slidingly placedover the multi-lumen tube. The proximal and distal ends of coil 139 arewound at a reduced pitch to allow the final coil to be positionedadjacent to the marker bands 146 a and 146 b. This produces a gradualstiffness transition to prevent kinking at the interface between thecoil 139 and the marker bands 146 a and 146 b. A covering ofpolyurethane 133 is then applied to contain the coil 139, and secure itin position over the multi-lumen tube of evacuation head 132. Thepolyurethane may be applied by a solvent casting of polyurethane in anappropriate solvent. Alternatively, in a currently preferred method, thestructure may be formed by applying a coating of UV curable polyurethanebetween multi-lumen/coil structure and a removable PTFE sleeve. Thecombination is then exposed to UV light and cured. The PTFE sleeve isthen removed from the structure leaving a smooth coating surface 133that encapsulates the coil 139.

[0092] The evacuation head 132 also contains a flare 131 on the proximalend 140 a of the evacuation lumen 140. This flare 131 is intended toallow for easier passage of devices through the proximal end 140 a ofthe evacuation lumen 140. The flare 131 can also create a clearance sealthat prevents the passage of fluid between the evacuation head 132 andthe guide catheter 160. This provides a sliding seal when the proximaland distal sealing balloons 134 and 136 are deflated.

[0093] Additionally, the evacuation lumen 140 has a distal end 140 bthat is angled. The angled distal end allows for the distal end 140 b tobe more flexible than the portion of the evacuation head 132 that isproximal to it. This is intended to reduce the trauma induced into thevessel during delivery of the evacuation head 132. Preferably, Thedistance from the end of the balloon 136 and the distal end of theevacuation lumen 140 b is minimized to reduce a chance of the evacuationlumen distal end 140 b from coming in contact with the vessel wall whilethe distal sealing balloon 136 is inflated. This is intended to preventthe obstruction of flow through the evacuation lumen 140. FIG. 11B is across-sectional view of the assembly shown in FIG. 11A.

[0094]FIG. 11C is an alternative embodiment of an evacuation sheathassembly according to the present invention. This embodiment is similarto that described in connection with FIGS. 11A and 11B, except that thedistal tip of the evacuation head 132 is cut perpendicular to the axisof the evacuation lumen 140 and proximate to the distal sealing balloon136. The perpendicular cut is useful when the anatomy is such that anangled distal end would contact the vessel wall in a way which limitsfluid flow through evacuation lumen 140. FIG. 11D is a cross-sectionalview of the assembly shown in FIG. 11C.

[0095] According to one aspect of the invention, the evacuation head 132includes at least one expandable sealing surface. As embodied herein andshown in FIG. 1A, two expandable sealing surfaces are provided. A firstproximal sealing surface is configured to form a seal within the guidecatheter which delivers the evacuation sheath assembly 100 to thesurgical site, as will be described. First proximal sealing surface ispreferably a proximal sealing balloon 134. A second distal sealingsurface is configured to form a seal within the blood vessel, as alsowill be described. Second distal sealing surface is preferably a distalsealing balloon 136. As shown in FIG. 1A, it is preferable that thedistal sealing balloon 136 be larger in size than the proximal sealingballoon 134. The proximal balloon 134 and the distal balloon 136 are influid communication with the inflation lumen 142 of evacuation head 132.Inflation lumen 142 is in fluid communication with a balloon inflationdevice 199 (see FIG. 5A). Although only a single inflation lumen 142 isshown, it is possible to use more than one inflation lumen. In such anembodiment, the multi-lumen tube 138 would comprise three lumens, twoinflation lumens, each one in fluid communication with one of thesealing balloons 134, 136, and one evacuation lumen. Each lumen would bein fluid communication with its own lumen extending proximally to aninflation device (not shown).

[0096] Preferably, the proximal and distal balloons 134, 136 are formedof an elastomer such as polyurethane or silicone. It is preferable toutilize elastomeric balloons, particularly for the distal sealingballoon 136, to allow the balloon to have a range of inflated diameters,depending on the volume of fluid infused into the balloon. Each sealingballoon 134, 136 includes two waist portions, one proximal 134 a, 136 aand one distal 134 b, 136 b of a body portion of the balloon. The waistsportions 134 a, 134 b, 136 a, 136 b are preferably secured to anexterior of the multi-lumen tube 138 using heat welding, solventbonding, or other suitable adhesive bonding techniques.

[0097] Although use of separate proximal and distal sealing balloons134, 136 is preferred, it is possible to instead use a singleelastomeric tube extending nearly the full length of the multi-lumentube 138. The single elastomeric tube would be secured to the outside ofthe multi-lumen tube 138 at the distal and proximal ends 140 b, 140 a ofevacuation lumen 140, as well as in the middle region of the evacuationlumen 140. In this manner, two expandable sealing surfaces are providedby the two regions of the single elastomeric tube which are not securedto the exterior of the shaft tube, i.e., the region between the proximalend 140 a and the middle region would form a proximal sealing surface,and the region between the distal end 140 b and the middle region wouldform a distal sealing surface.

[0098] As embodied herein, the balloons 134, 136 may be blow molded fromtubing or dip molded to approximate the shape and minimum anticipateddiameter of their final inflated condition. Particularly for the distalsealing balloon 136, further inflation would further increase thediameter, as the balloon is preferably elastomeric. Alternatively,however, the balloons need not be pre-molded to the expanded shape. Insuch a variation, each balloon 134, 136 is preferably a uniform diametertube between the two balloon waists 134 a, 134 b, 136 a, 136 b. As theuniform diameter tubes are preferably elastomeric materials, they can beelastically expanded to the same shape and size as the alternativepre-molded balloons. The non-pre-molded balloons would require a higherinflation pressure to expand to a particular dimension. Furthermore, thenon-pre-molded elastomeric balloons would deflate more easily, as theelasticity would help to force the inflation fluid from the interior ofthe balloons. To improve the range of expandability of the elastomericballoons, it is preferable for the body portion of each balloon 134, 136to have a length at least as great as the maximum inflated diameter, andmore preferably several times longer, for example about 3-4 timeslonger.

[0099] While it is preferred to provide the two expandable sealingsurfaces of two elastomeric balloons 134, 136, as described above, it ispossible to fabricate the proximal sealing balloon 134 of anon-elastomeric polymer molded to the shape and size as shown in FIG.1A. Since the proximal balloon 134 is intended to be inflated within theguide catheter, it is only necessary for the proximal balloon 134 to beinflated against the internal diameter of the guide catheter. The distalsealing balloon 136, however, preferably has a relatively wide range ofexpanded diameters, and therefore benefits from being elastomeric.Additionally, if the distal sealing balloon 136 is elastomeric, and theproximal sealing balloon 134 is fabricated of a pre-molded thin walledpolymer such as PET or nylon, and if both balloons are inflated from acommon inflation lumen 142, then the proximal sealing balloon 134 willexpand against the internal surface of the guide catheter, causing aseal, prior to any significant expansion of the distal sealing balloon136 beyond its initial dimension.

[0100] As discussed earlier, the evacuation sheath assembly 100 isconfigured to be used with a guiding catheter 160 (see FIGS. 5A and 6A).The guiding catheter 160 performs an evacuation function in combinationwith the evacuation lumen 140. The guiding catheter 160 also maintains acontrast delivery function. The evacuation head 132, with its twosealing balloons 134, 136 inflated, is intended to isolate fluidcommunication of the internal lumen of the guide catheter 160 to theblood vessel 150 in which it is inserted. Preferably, proximal anddistal radiopaque markers 146 a, 146 b are placed at the site of eachballoon 134, 136. Alternatively, two markers may be placed proximallyand distally adjacent to each balloon 134, 136. The proximal and distalradiopaque markers 146 a, 146 b allow the operator to radiographicallyposition the two sealing balloons 134, 136 in the proper location withinthe guiding catheter 160 and the blood vessel 150.

[0101] In use, the distal balloon 136 is intended to be positioneddistal of the distal tip of a guiding catheter 160 and inflated againstthe inside surface of the blood vessel 150 causing a fluid tight sealbetween the blood vessel 150 and the balloon 136. The proximal balloon134 is intended to be positioned proximal of the distal end of theguiding catheter 160 and inflated against the guiding catheter 160causing a fluid tight seal.

[0102] The preferred inflated diameters of the sealing balloons 134, 136are thus determined by the intended application. For example, if theevacuation sheath assembly 100 is intended to be used in a diseasedsaphenous vein bypass graft, (SVG), a guiding catheter of 8 French maybe utilized. The proximal sealing balloon 134 will therefore require aninflated diameter capable of sealing against the inside of the guidingcatheter, typically in the range of about 0.088-0.096 inches. The distalsealing balloon 136 will need to be capable of sealing against theinside of the SVG, which typically has an inside diameter ranging fromabout 2.5-6 mm.

[0103] The length of the evacuation head 132 is dependent on theapplication for which the evacuation sheath assembly 100 is intended tobe used. It is intended that the evacuation head 132 be long enough forthe proximal sealing balloon 134 to be sealingly inflated within theguide catheter 160, and the distal sealing balloon 136 to be sealinglyinflated within the blood vessel of interest. In many applications,therefore, evacuation head 132 can be relatively short. For example, inthe case of an SVG application, this length may be on the order of 2 to5 cm. However, in a native coronary artery application, particularly inthe left coronary circulation, it may be desired to have the evacuationhead 132 longer, such that the distal sealing balloon 136 is positionedbeyond the first or other main bifurcation. For example, it may bedesired to position the distal sealing balloon 136 within the leftanterior descending artery, distal of the left main artery. For thisapplication, the evacuation head 132 is preferably about 5 to about 20cm in length.

[0104] The diameter of the evacuation head 132 is also dependent on theintended application. As an example, preferred dimensions are describedhere with respect to an application in SVGs, with use of an 8 Frenchguide catheter whose inner diameter is about 0.090 inches. Theevacuation lumen 140 may be approximately 0.061 inches, which will allowthe passage of most therapeutic devices such as angioplasty catheters,stent delivery catheters, atherectomy catheters, drug deliverycatheters, etc. The inflation lumen 142 may have a dimension of about0.005 inches at the widest portion of the crescent (vertical directionin FIG. 1B). The wall thickness for most of the multi-lumen tube wall138 may be about 0.002 inches, and the balloon waist thickness may beapproximately 0.002 inches. These dimensions create an evacuation head132 having a maximum diameter (in delivery condition) of about 0.076inches, less than the inner diameter of the guide catheter 160.

[0105] According to another aspect of the invention, the evacuationsheath assembly 100 includes a shaft. As embodied herein and shown inFIG. 1A, the shaft includes a proximal shaft portion 110, anintermediate shaft portion 120, and a distal shaft portion 130 (notshown in FIG. 1A, shaft portion 130 includes evacuation head 132).

[0106] Proximal shaft portion 110 forms a hollow tube. Preferably,proximal shaft portion 110 is made of stainless steel, however, otherstructures and materials, such as polymer and metallic composites,(e.g., braid reinforced polymer tubes), nickel-titanium alloy, or othersuitable materials exhibiting appropriate biocompatibility andflexibility properties may be used. The proximal shaft portion 110provides fluid communication between an inflation apparatus (not shown)and the intermediate and distal shaft portions 120, 130. The proximalshaft portion 110 may also be coated with a polymer sleeve or spraycoating for lubricity.

[0107] Preferably, the proximal shaft portion 110 includes markers 115on its exterior surface. These markers 115 are positioned to indicate toa user that the evacuation sheath assembly 100 has been advanced throughthe guiding catheter 160 to a location where the distal end of theevacuation sheath assembly 100 is just proximal to the distal end of theguiding catheter 160. The proximal shaft portion 110 is preferablysecured to a luer hub 105, for example by an overlapping weld oradhesive bond joint. The luer hub 105 allows the evacuation sheathassembly 100 to be connected to an inflation apparatus for the inflationof the sealing balloons 134, 136. Any suitable inflation device may beused, including those resident in hospital cath labs.

[0108] An intermediate shaft portion 120 is secured to the proximal anddistal shaft portions 110, 130, preferably by an overlapping weld orbond joint. Intermediate shaft portion 120 forms a hollow tube.Intermediate shaft portion 120 is preferably formed of polyethylene orPebax, however, other polymers and polymer metallic composites, such aspolyimide with an incorporated braid of stainless steel wire, or othersuitable material exhibiting appropriate biocompatibility andflexibility characteristics, may be used. The intermediate shaft portion120 provides fluid communication between the proximal shaft portion 110and the distal shaft portion 130. The intermediate shaft portion 120also transmits longitudinal force from the proximal shaft portion 110 tothe distal shaft portion 130. The intermediate shaft portion 120 ispreferably more flexible than the proximal shaft portion 110, to allownavigation of the curves within the distal region of the guidingcatheter, as are often present, particularly in cardiac relatedapplications.

[0109] A distal end of the intermediate shaft portion 120 is connectedto a distal shaft portion 130, preferably by welding or bonding. Distalshaft portion 130 includes the inflation lumen 142 of multi-lumen tube138 and a soft distal tip portion 144. As shown in FIG. 1A, theinflation lumen 142 is in fluid communication with the proximal shaftportion 110 and intermediate shaft portion 120. The distal end ofinflation lumen 142 ends in a solid portion forming the distal end ofthe distal shaft portion 130. The distal end of the distal shaft portion130 is tapered to form soft tip 144. The soft tip 144 may comprise amore flexible polymer secured to the distal end of the multi-lumen tube138 of the evacuation head 132. For example, if the multi-lumen tube 138is fabricated of high density polyethylene, the soft tip 144 may befabricated of a low durometer polyurethane or Pebax. The soft tip 144allows the evacuation sheath assembly 100 to be placed atraumaticallyinto the blood vessel, even if the blood vessel exhibits tortuosity.

[0110] The shaft of the evacuation sheath assembly preferably includes astiffness transition member 135. Stiffness transition member 135 isattached to the distal end of the proximal shaft portionl 10, forexample by welding or bonding. The stiffness transition member 135 ispreferably made of stainless steel, but other metals such as nickeltitanium alloy or polymers may be used. The stiffness transition member135 is located co-axially in the inflation lumen 142 (as shown in FIG.1B) and extends from the proximal shaft portion 110 to the soft tip 144.A distal end 137 of the stiffness transition member 135 preferablyincludes a spring tip embedded into the material of the soft tip 144.Embedding the spring tip into the soft tip 144 allows the stiffnesstransition member 135 to prevent longitudinal stretching or compressingof the evacuation sheath assembly 100.

[0111] Alternatively, the distal end 137 of the stiffness transitionmember 135 can have a enlarged welded ball or other shape which canserve to mechanically interlock the stiffness transition member 135within the soft tip 144. The portion of the stiffness transition member135 within the tip 144 of the evacuation sheath assembly 100 also servesto allow the tip to be formed in a “J-bend”, similar to that forcoronary guide wires. The stiffness transition member 135 can thentransfer rotational forces and motion imparted from the proximal regionof the evacuation sheath assembly 100 to the tip 144, to facilitatesteering and navigation of the evacuation head 132 to a desired site inthe blood vessel.

[0112] The stiffness transition member's bending stiffness decreasesgradually from the proximal end to the distal end of the stiffnesstransition member 135. Preferably, this is accomplished by reducing thecross sectional area of the member 135 as shown in FIG. 1A, wherestiffness transition member 135 includes three portions of decreasingdiameter 135 a, 135 b, 135 c from proximal to distal end. However, thiscan also be accomplished by changes in shape and/or materials. Thestiffness transition member 135 allows for a gradual stiffness reductionin the evacuation sheath assembly 100, which allows it to more smoothlynavigate the curves of the guiding catheter and the blood vessel. Thisshaft construction is exemplary only, and is not intended to limit theinvention.

[0113] As mentioned, although described herein with respect to stentplacement in an SVG or coronary artery having a stenosis, evacuationsheath assembly 100 may be used in other surgical procedures and withother therapeutic devices, such as balloon angioplasty, atherectomy,thrombectomy, drug delivery, radiation, and diagnostic procedures.

[0114] As embodied herein and shown in simplified drawing FIG. 6A, thelumen of a blood vessel 150 is accessed with the distal end of a guidingcatheter 160, which is well known in the art and typical forcoronary-type procedures. A coronary guide wire 170 then is advanced toa location just proximal to the distal tip of the guiding catheter 160.Blood flow at this point remains in the direction of normal arterialblood flow. The blood is flowing around and past the distal tip of theguiding catheter 160 and through the stenosis 180 as indicated by arrows190.

[0115] As shown in FIG. 6B, the evacuation sheath assembly 100 then isadvanced over the guide wire 170 and positioned within the vessel 150with the distal radiopaque marker 146 b distal of the distal tip of theguiding catheter 160 (i.e., within the vessel 150) and the proximalmarker 146 a proximal of the distal tip of the guiding catheter 160(i.e., within catheter 160), as determined through appropriate imagingtechniques known in the art. Alternatively, the guide catheter 160 maybe positioned within the ostium of the target vessel, and the evacuationsheath assembly 100 may be advanced through the catheter and beyond amajor side branch of the target vessel.

[0116] Blood flow continues to be in the direction of normal arterialblood flow as shown by arrows 190. Because the assembly 100 has asrelatively short evacuation head 132, the entire evacuation sheathassembly 100 can be advanced over a conventional length coronary guidewire 170 after the guide wire 170 has been placed within the guidecatheter 160.

[0117] Once the evacuation head 132 is positioned with its distal endwithin the vessel 150 while its proximal end remains in the catheter160, the distal and proximal sealing balloons 136, 134 are inflated asshown in FIG. 6C. The distal sealing balloon 136 provides a fluid tightseal between the sealing balloon 136 and the blood vessel 150 and theproximal sealing balloon 134 provides a fluid tight seal between thesealing balloon 134 and the interior diameter of the guiding catheter160. A suitable valve 184, such as a touhy borst valve, attached to theguiding catheter 160 (shown in FIG. 5A) provides a fluid tight sealagainst the guide wire 170 and the proximal shaft portion 110 of theevacuation sheath assembly 100. The three fluid tight seals establishfluid communication between the distal end of the evacuation sheathassembly 100 and a fluid collection chamber, filter, and vacuum source188, which is attached to the Y-adaptor (conventional) 184 shown in FIG.5A. A blood pressure transducer 192 is commonly connected in fluidcommunication with the lumen of the guide catheter 160 (throughadditional stop cocks or manifolds as is well-known in the art) tomonitor arterial blood pressure. As the sealing balloons 134, 136 areinflated to establish the fluid communication of the evacuation sheathassembly and guide catheter 160 with the collection chamber, filter, andvacuum source 188, the blood pressure waveform can be observed to changefrom a relatively high pressure and pulsatile waveform of the artery, toa relatively low and constant waveform of the venous pressure. Thispressure observation is an important indicator that the sealing balloons134, 136 have effectively isolated fluid communication to the coronaryartery. With the three fluid tight seals in place, a normal antegradeflow within the artery is stopped. Thus, there is substantially no bloodflow within the vessel 150, as indicated by the lack of arrows in FIG.6C.

[0118] At this point, it may be desirable to inject a small amount ofcontrast into the blood vessel, via a dye injection apparatus 189 influid communication with the guide catheter 160, evacuation head 132,and blood vessel 150, to aid in navigation of the guide wire 170 acrossthe stenosis 180. The evacuation lumen 140 of the evacuation head 132becomes an extension of the guide catheter lumen for this contrastdelivery. Because normal antegrade blood flow in the coronary artery hasbeen effectively stopped, the contrast will remain in the coronaryartery, rather than quickly washing away. This may be advantageous forthe subsequent navigation of the guide wire 170.

[0119] Once antegrade flow is stopped, as shown in FIG. 6C, the guidewire 170 is advanced across the stenosis 180. In most cases, to beginadvancing the guide wire 170, the touhy borst valve 184 on the Y-adaptor(shown in FIG. 5A) will need to be opened just enough to allow formovement of the wire 170, but not so much to allow vigorousbackbleeding. In the procedure described here, it is preferred to openthe valve only enough such that there is little to no backbleeding,otherwise the venous pressure head in the coronary artery can causeretrograde flow during this step, thereby pushing all of the contrastback into the guide catheter and out of the blood vessel.

[0120] Once the wire has crossed the stenosis 180, it may be desirableto cause retrograde flow in the coronary artery (FIG. 6D), as the act ofcrossing a stenosis 180 with a wire 170 (particularly a fragile lesion(stenosis), such as in an SVG) may in itself dislodge material. Anymaterial dislodged will not travel downstream, as the antegrade flow hasalready been stopped. Retrograde flow can be used to remove thedislodged material.

[0121] With all seals in place, blood flow may now be established fromthe distal end of the evacuation head 132 to the collection chamber, andfilter 188 to remove any dislodged material. Retrograde flow isrepresented in FIG. 6D by arrows 195. This retrograde flow is due to thevenous pressure head, and will begin once the pressure in the collectionbottle 188 is vented to atmospheric pressure. Flow can also be increasedby applying vacuum to the collection chamber and filter 188. Thisretrograde flow will carry any dislodged material out of the patient andinto a collection chamber. The collection chamber may be a simplesyringe or may be any other suitable container. If a syringe is used,withdrawal of the plunger automatically causes a vacuum to induceretrograde flow. After enough volume has been removed, the flow can bestopped by closing the valve to atmosphere pressure or by releasing thevacuum. If desired, after any dislodged material has been removed, theballoons 134, 136 of the evacuation sheath assembly 100 may betemporarily deflated, allowing for a period of antegrade blood flow andperfusion of the vessel 150.

[0122] After any dislodged material has been removed, and after normalantegrade blood flow has been allowed, if so desired, all seals areagain established. With all seals in place, a therapeutic device such asa stent delivery system 193 is advanced across the stenosis 180 withantegrade flow stopped, as shown in FIG. 6E. The touhy borst valve 184attached to the guide catheter 160, which is shown in FIG. 5A, sealsagainst the proximal end of the therapeutic device, the guide wire 170and the proximal shaft portion 110 of the evacuation sheath assembly100. Alternatively, advancement of the delivery system may be done withretrograde flow. In a step similar to that for the guide wireadvancement, some contrast may be delivered into the vessel, allowingcontinuous visualization of the vessel and stenosis for more preciseplacement of the stent delivery catheter 193. Again, to effectively keepthe contrast in place, the touhy borst valve 184 through which the stentdelivery catheter 193 passes must be opened just enough to allow foradvancement of the device with little to no backbleeding.

[0123] Once the stent delivery system 193 is accurately positionedadjacent the stenosis 180, a stent delivery balloon is inflated toexpand a stent 194 against the vessel wall, opening a passage for bloodflow through the stenosis 180 (FIG. 6F). During inflation of the stentballoon, retrograde flow (if present) is discontinued by the occlusionof the blood vessel by the therapeutic device and the stoppage of anyapplied vacuum.

[0124] After the stent 194 is applied to the stenosis 180, the stentdelivery balloon is deflated and retrograde flow is re-established inthe vessel 150. Any embolic material 197 dislodged from the therapeuticsite is carried back to the evacuation lumen 140 of the evacuation head132 by the retrograde flow 195 (FIG. 6G). The embolic material 197 mayinclude material dislodged during advancement of the therapeutic device,or during the expansion of the stent 194, in the case where thetherapeutic device includes a stent 194. To remove this potentiallyembolic debris 197, the retrograde flow 195 is re-established when thetherapeutic device is no longer occluding the blood flow, and additionalvacuum is preferably applied to the evacuation lumen 140. Thetherapeutic device may be left in place while there is retrograde flow,or it may be positioned proximal to the stenosis 180, or even broughtback within the lumen of the guide catheter 160. In some instances, oncethe particulate 197 has been removed, additional contrast delivery tothe blood vessel may indicate a need for more therapeutic steps, e.g.,further dilation of the stent with the balloon. In this case, it is moreconvenient to have the balloon catheter already in position for anysubsequent use.

[0125] After the embolic material is removed, the therapeutic device isremoved from the vessel 150 (retrograde flow may or may not bemaintained) (FIG. 6H). The distal and proximal sealing balloons 136, 134are then deflated (FIG. 6I), establishing normal arterial flow.

[0126] According to another aspect of the present invention, thediameter of an evacuation head may be expandable from a firstintroduction diameter to a second operational diameter. As embodiedherein and shown in FIGS. 2A-2D, an evacuation sheath assembly 200 isprovided with an expandable evacuation head 232. Many of the elementspresent in the previous embodiment are also shown in FIGS. 2A-2D andwhere these elements are substantially the same, similar referencenumerals have been used and no detailed description of the element hasbeen provided.

[0127] As shown in FIG. 2B, the evacuation head 232 preferably includesan inner layer 226 that will serve as an evacuation lumen and an outerlayer 228 that will serve as the sealing surfaces. Preferably, the innerlayer 226 is fabricated from polyethylene PET or Pebax, but othersuitable materials may be used. The evacuation head 232 has a proximalend 232 a and a distal end 232 b. FIGS. 2A and 2B show the evacuationhead 232 in an unexpanded state and FIGS. 2C, 2D, and 2E show theevacuation head 232 in an expanded state. The inner layer 226 of theevacuation head 232 preferably comprises a tube that unfolds to increasein diameter. In FIG. 2C, the increase in diameter assumes a step-wiseshape. Thus, preferably, a distal portion of the inner layer 226 of theevacuation head has an expanded diameter which is larger than a diameterof a guide catheter 260.

[0128] The expanded shape of the inner layer 226 of the expandableevacuation head 232 may include a proximal portion having a firstdiameter and a distal portion having a second diameter, the seconddiameter being larger than the first such that the inner layer 226 ofthe evacuation head 232 has a larger dimension in the region whichresides within the blood vessel, as shown in FIG. 2C. Alternatively, thediameters of the proximal and distal portions of the inner layer 226 ofthe evacuation head 232 may be the same, such that the diameter of anexpanded inner layer 226 is the same for the region outside of the guidecatheter as the region which resides within the guide catheter. In suchan embodiment, it would be necessary to provide the distal portion ofthe evacuation head 232 with a larger or more expansible outer layer,i.e., sealing surface (distal sealing balloon), to ensure a proper sealwith blood vessel 250.

[0129] The distal and proximal ends of the expanded evacuation head 232may be angled relative to its longitudinal axis, as discussed withrespect to the embodiment shown in FIG. 1A, although this is not shownin FIGS. 2A-2D. The low profile folded delivery state of the evacuationhead 232 may not require such angles. Furthermore, if the distal end ofthe head 232 is not angled relative to the longitudinal axis, the entireopen distal end of the expandable evacuation head 232 is suitable forpositioning close to the desired therapy site.

[0130] The outer layer 228 of evacuation head includes multiplespherical balloons (or balloon regions) 233, including a proximal mostballoon 234 and a distal most balloon 236, with a cylindrical waistbetween each balloon. The inner and outer layers 226, 228 of theevacuation head 232 may be seam welded or bonded together around thecircumference at each waist location, while the inner layer 226 is inits expanded condition. Prior to insertion of the evacuation sheathassembly 200 into the guide catheter 260, the evacuation head 232 isfolded into its unexpanded condition, as shown in FIGS. 2A and 2B. Whenfluid, either a gas or liquid, is infused between the inner and outerlayers, the outer layer 228 expands radially. As the outer layer 228expands into multiple balloon regions 233, it pulls the inner layer 226with it, opening the evacuation lumen 240. Thus, the inner and outerlayers expand together in the radial direction when inflated.

[0131] As discussed with respect to the embodiment shown in FIGS. 1A-1C,the evacuation head 232 comprises a multi-lumen tube 238 having anevacuation lumen 240 and an inflation lumen 242. As in the embodimentshown in FIGS. 1A-1C, the inflation lumen 242 is in fluid communicationwith intermediate and proximal shaft portions 210, 220 and is in fluidcommunication with the individual balloon segments 233, 234, 236, suchthat when fluid is infused into inflation lumen 242, the evacuation head232 expands. Further infusion of fluid into the inflation lumen of theevacuation sheath assembly will inflate the distal and proximal sealingballoons until they are appropriately sized to cause effective sealing.

[0132] As described previously, in addition to intermediate balloons233, the evacuation head 232 includes a proximal sealing balloon 234 anda distal sealing balloon 236. The proximal sealing balloon is configuredto seal with an inner diameter of the guide catheter 260 and the distalsealing balloon is configured to seal with the inner walls of bloodvessel 250. The remaining balloons 233 need only be sized to an inflateddiameter sufficient to “pull” open the inner layer 226 of the expandableevacuation head 232. Although three intermediate balloons 233 are shownin FIG. 2C, more or fewer balloons may be provided as appropriate, forexample depending upon the length of the evacuation head to be expanded.Although intermediate balloons 233 are intended to “pull” openevacuation lumen 240 of the evacuation head 232, balloons 233 may alsoprovide addition sealing under certain circumstances, as shown in FIG.2C. However, it is less important that the remaining balloons 233 beelastomeric, as they do not necessarily require a range of expandeddiameters.

[0133] As shown in FIGS. 2A and 2B, prior to insertion into the guidecatheter 260, the evacuation head 232 is folded into a reduced diameterconfiguration. As illustrated, this folding may be in a generally “w”type fold, however other folding configurations are contemplated, suchas “s” folds or “c” folds. It is also preferable to heat set the foldedevacuation head 232 in this configuration. Because the evacuation headhas been heat set in a folded configuration, once the sealing balloonsand remaining balloons are deflated after a procedure, the evacuationhead will refold toward its pre-expanded configuration.

[0134] The low profile of the evacuation head 232 in its deliveryconfiguration and the soft tip 244 at the end of evacuation sheathassembly 200 allow the expandable evacuation sheath assembly 200 to bepassed through smaller and more tortuous lumens and blood vessels. Theexpandable evacuation lumen 240 also allows the evacuation sheathassembly 200 to be sized more closely to the guiding catheter 260 andlarger than the guiding catheter 260 in the portion that is placeddistal of the guiding catheter when it is in the expanded state. Thislarger lumen allows for high evacuation flow rates, and eases theability for large particles to be removed from the blood vessel duringor subsequent to the therapeutic procedure, while having a relativelysmall collapsed delivery condition.

[0135] In use, the evacuation sheath assembly 200 is deployed in asimilar manner as discussed with respect to evacuation sheath assembly100. The steps for using evacuation sheath assembly 200 with a guidecatheter 260 in a vessel 250 are sequentially depicted in FIGS. 7A-7I.

[0136] As shown in FIG. 7A, guide catheter 260 and guide wire 270 areadvanced proximate to a blood vessel 250. Subsequently, evacuationsheath assembly 200, with evacuation lumen 240 in its deliveryconfiguration, is advanced over the guidewire 270 into guide catheter260 and blood vessel 250 (FIG. 7B). Once evacuation head 232 is properlypositioned, as can be verified using proximal markers 115 and markers246 a, 246 b, evacuation head 232 is expanded (FIG. 7C) until evacuationlumen 240 is open. Fluid continues to be injected into the balloonsuntil proximal balloon 234 creates a seal with the lumen of guidecatheter 260 and until distal balloon 236 creates a seal with bloodvessel 250. After the proper seals are established, the stenosis 280 istreated and any embolic debris 297 is removed via retrograde flow 295(FIGS. 7C-7H), as previously described with respect to FIGS. 6C-6H.After treatment, evacuation head 232, including proximal and distalsealing balloons 234, 236, is deflated and then removed from bloodvessel 250 (FIG. 7I).

[0137] According to another aspect of the present invention, theevacuation head may comprise an elongated multi-lumen tube. As embodiedherein and shown in FIGS. 3A and 3B, an evacuation sheath assembly 300is provided with an evacuation head 332. Many of the elements present inthe previous embodiments are also shown in FIGS. 3A and 3B and wherethese elements are substantially the same, similar reference numeralshave been used and no detailed description of the element has beenprovided.

[0138] As shown in FIG. 3A, evacuation head 332 includes a singleelongated multi-lumen tube 338. The size of the tube 338 allows it to beplaced through a guiding catheter 360 and into a blood vessel 370 (seeFIG. 5C). The tube may be made from a polymer such as polyethylene orPebax® material or materials described with respect to FIG. 1A. Inaddition, the tube 338 may include a coil or braid, as in FIG. 1C, inall or only portions of the tube. The multi-lumen tube 338 includes twolumens 340, 342. The larger of the lumens, the evacuation lumen 340, isdesigned to allow for the passage of interventional devices such as, butnot limited to stent delivery systems and angioplasty catheters. Thelumen is also designed to allow for fluid flow, such as blood,blood/solid mixtures, radiographic dye and saline, within the lumen asdiscussed with respect to FIGS. 1A-1C.

[0139] A distal end of the tube 338 is tapered into a soft tip 344, asdescribed in connection with previous embodiments. The soft tip 344allows the evacuation sheath assembly 300 to be placed more smoothlyinto the blood vessel. The tube 338 includes inflation lumen 342, whichallows for fluid communication between the proximal end of theevacuation sheath assembly 300 and an expandable sealing surface. Theelongated multi-lumen tube 338 defines the entire evacuation lumen 340,unlike the devices shown in FIGS. 1A-2D which make use of a significantlength of the lumen of the guide catheter for evacuation. For thisreason, only a single expandable sealing surface is required.

[0140] The expandable sealing surface is preferably a distal sealingballoon 336. Distal sealing balloon 336 may comprise an elastomericmaterial such as polyurethane or silicone. The distal sealing balloon336 is configured be positioned distal of the distal tip of a guidingcatheter 360 and inflated against the blood vessel 350 causing a fluidtight seal between the blood vessel 350 and the balloon 336. Radiopaquemarker 346 is preferably placed at the site of the sealing balloon 336.The radiopaque marker 346 allows the operator to radiographicallyposition the sealing balloon 336 in the proper location within the bloodvessel 350. A proximal shaft portion 310 of the evacuation sheathassembly 300 is sealed against a valve 384, such as a touhy borst valve,on the guide catheter 360 creating a fluid tight seal against theevacuation sheath assembly 300 and the guiding catheter 360.

[0141] The tube 338 includes proximal markers 315 placed on the exteriorof the proximal portion of the tube 338. These markers 315 arepositioned to indicate that the tube 338 has been advanced through theguiding catheter 360 to a location where the distal end of theevacuation sheath assembly 300 is just proximal to the distal end of theguiding catheter 360. A proximal portion of the tube 338 is secured to abifurcated luer hub 305 by an overlapping weld or bond joint. Thebifurcated luer hub 305 includes an inflation port 302 and a vacuum port303 which allows the evacuation sheath assembly 300 to be connected toan inflation apparatus and a vacuum source, respectively.

[0142] In use, the evacuation sheath assembly 300 is deployed in asimilar manner to that discussed with respect to evacuation sheathassembly 100. The steps of using evacuation sheath assembly 300 with aguide catheter 360 in a vessel 350 are sequentially depicted in FIGS.8A-8I. The differences between the method discussed with respect toevacuation sheath assembly 100 and that for evacuation sheath assembly300 are discussed below.

[0143] Because the lumen in evacuation sheath assembly 300 runs the fulllength of evacuation sheath assembly 300, the evacuation sheath assembly300 should be inserted together with the coronary guide wire 370. Also,because the lumen of the guide catheter 360 is more fully obstructed bythis evacuation sheath assembly 300, it is preferable to inject contrastdirectly into the proximal end of the evacuation lumen 340 of theevacuation sheath assembly 300 (or into both lumen 340 and the lumen ofguide catheter 360), rather than just into the lumen of the catheter360. Also, both the guide catheter lumen and the evacuation lumen 340can be used for pressure monitoring, although it is more desirable touse the evacuation lumen 340 for pressure monitoring to confirm a tightseal between the distal balloon 336 and blood vessel 350 as needed. Asopposed to the earlier discussed embodiments, only one sealing balloon336 is used to provide the seal in the evacuation sheath assembly 300,as shown in FIGS. 8C-8H.

[0144] Thus, as shown in FIG. 8A, guide catheter 360 is positionedwithin blood vessel 350. Then evacuation sheath assembly 300 is advancedwith guidewire 370 into blood vessel 350 (FIG. 8B). Proper positioningof a distal end of evacuation sheath assembly 300 may be confirmed usingdistal marker 346. Then distal sealing balloon 336 is inflated viainflation port 302, stopping blood flow within blood vessel 350. Ifdesired, contrast dye may be injected through evacuation lumen 340 intoblood vessel 350 to view blood vessel 350 prior to treating stenosis380. Stenosis 380 is then treated and any embolic debris 397 is removedvia retrograde flow 395 through evacuation lumen 340 (FIGS. 8C-8H), aspreviously described with respect to FIGS. 6C-6H. After treatment,distal sealing balloon 336 is deflated and evacuation sheath assembly300 is removed from blood vessel 350 (FIG. 8I).

[0145] According to another aspect of the present invention, theevacuation sheath assembly may comprise an elongated multi-lumen tubewhich eliminates the need for a separate guiding catheter. As embodiedherein and shown in FIGS. 4A and 4B, an evacuation/guiding sheathassembly 400 is provided with an evacuation/guiding lumen 440. Many ofthe elements present in the previous embodiments are also shown in FIGS.4A and 4B and where these elements are substantially the same, similarreference numerals have been used and no detailed description of theelement has been provided.

[0146] As shown in FIG. 4A, evacuation/guiding sheath assembly 400includes a single elongated multi-lumen tube 438. The size of the tube438 allows it to be used as a combination guiding catheter andevacuation lumen, to deliver interventional devices into a blood vessel450. The multi-lumen tube 438 is preferably formed of a Pebax®,stainless steel and PTFE composite material, very similar toconventional guide catheters, well known in the art, with the exceptionthat an additional lumen in the wall of the tube is provided. Tube 438can be made of other suitable polymers and metal materials. Themulti-lumen tube 438 includes first and second lumens. The larger of thelumens, the evacuation/guiding lumen 440, is designed to allow for thepassage of interventional devices such as, but not limited to, stentdelivery systems and angioplasty catheters. The lumen 440 is alsodesigned to allow for fluid flow, such as blood, blood/solid mixtures,radiographic dye and saline, within the lumen. This flow of fluid isallowed with or without an interventional device in theevacuation/guiding lumen 440.

[0147] The tube 438 can be pre-formed in various curvatures duringmanufacturing to allow for easy access to the ostium of severaldifferent blood vessels in a manner similar to conventional guidecatheters as known in the art. Note that FIGS. 4A and 4B do not showthese pre-formed curves. The distal end of the tube 438 is preferablyfitted with a more flexible material, forming a soft distal tip 444.This flexible tip 444 allows the evacuation/guiding lumen 440 to beplaced more smoothly into the blood vessel. The tube 438 also containsan inflation lumen 442, which allows for fluid communication between aproximal end of the evacuation/guiding sheath assembly 400 and anexpandable sealing surface on a distal end of the evacuation/guidingsheath assembly 400.

[0148] Preferably, the expandable sealing surface is an inflatablesealing balloon 436. The sealing balloon 436 is preferably elastomericand may comprise polyurethane or silicone, similar to that of the distalsealing balloon of FIGS. 1A-1C. The sealing balloon 436 is intended tobe positioned distal of the ostium of the blood vessel 450 and inflatedagainst the blood vessel 450 causing a fluid tight seal between theblood vessel 450 and the balloon 436. Radiopaque markers 446 arepreferably placed at the site of the sealing balloon 436 to allowradiographically verifying the position of the sealing balloon 436. Theproximal portion of the tube 438 is sealed against a interventionaldevice by a bifurcated touhy borst valve 484 attached to theevacuation/guiding sheath assembly 400 to create a fluid tight sealagainst the evacuation/guiding sheath assembly 400 and theinterventional device.

[0149] A proximal portion of the tube 338 is secured to the bifurcatedtouhy borst luer hub 484 by an overlapping weld or bond joint. Thebifurcated luer hub allows the evacuation sheath assembly to beconnected to an inflation apparatus and a vacuum source through aninflation port 402 and a vacuum port 403, respectively.

[0150] The steps of using evacuation/guiding sheath assembly 400 aresequentially depicted in simplified FIGS. 9A to 9H. Use ofevacuation/guiding sheath assembly 400 is similar to the methoddescribed with respect to evacuation sheath assembly 100. Thedifferences between the method discussed with respect to FIGS. 6A-6I andthat for evacuation/guiding sheath assembly 400 are discussed below.

[0151] The lumen of the blood vessel 450 is accessed with the distal tip444 of the evacuation/guiding sheath assembly 400. A guide wire 470 isadvanced to a location just proximal to the distal tip 444 of theevacuation/guiding sheath assembly 400 (FIG. 9A). Blood flow at thispoint remains in the direction of normal arterial blood flow as shown byarrows 490. The evacuation/guiding sheath assembly 400 is thenpositioned with the distal marker band 446 distal of the ostium of theblood vessel 450. Once the positioning of the distal tip 444 of theevacuation/guiding sheath assembly 400 is verified, the distal sealingballoon 436 is inflated as shown in FIG. 9B to stop normal antegradeflow. The distal sealing balloon 436 provides a fluid tight seal betweenthe sealing balloon 436 and the blood vessel 450. Alternatively, thedistal sealing balloon 436 may be shaped such that it seals against theaortal surface and the most adjacent portion of the coronary ostium (notshown).

[0152] A touhy borst valve 484 attached to the evacuation/guiding sheathassembly 400 (shown in FIG. 5D) provides a fluid tight seal around theguide wire 470. The two fluid tight seals establish fluid communicationbetween the distal end of the evacuation/guiding sheath assembly 400 anda fluid collection chamber, filter, and vacuum source 488, which isattached to the bifurcation lumen of the touhy borst valve 484 shown inFIG. 5D, and stop normal antegrade blood flow within blood vessel 450. Ablood pressure transducer 492 is commonly connected in fluidcommunication with the lumen of the guide catheter to monitor arterialblood pressure.

[0153] If desired, contrast dye may be injected throughevacuation/guiding lumen 440 into blood vessel 450 prior to treatingstenosis 480. Stenosis 480 is then treated and any embolic debris 497 isremoved via retrograde flow 495 through evacuation/guiding lumen 440(FIGS. 9C-9G) as previously described with respect to FIGS. 6C-6H. Aftertreatment, distal sealing balloon 436 is deflated and evacuation/guidingsheath assembly 400 is removed from blood vessel 450 (FIG. 9H).

[0154] According to another aspect of the present invention, thediameter of an evacuation head may be expandable from a firstintroduction diameter to a second operational diameter. As embodiedherein and shown in FIGS. 10A-10D, an evacuation sheath assembly 500 isprovided with an expandable evacuation head 532. Many of the elementspresent in the previous embodiment are also shown in FIGS. 10A-10D andwhere these elements are substantially the same, similar referencenumerals have been used and no detailed description of the element hasbeen provided.

[0155] The evacuation head 532 of the present embodiment is similar tothe first and second embodiments previously discussed in that theevacuation sheath assembly 500 comprises a relatively short evacuationhead 532. Evacuation sheath assembly 500 also makes use of the guidecatheter 560 to form a part of an evacuation lumen 540.

[0156] As shown in FIG. 10A, evacuation head 532 includes a tube 538having a single expandable lumen, evacuation lumen 540. Evacuation head532 may have a naturally unexpanded state. Alternatively, evacuationhead 532 may be designed to normally be in an expanded state. However,it is preferred to have the evacuation head 532 fabricated to have itsnatural shape and size in the reduced dimension, as shown in FIG. 10B.

[0157] The evacuation head 532 includes two sealing surfaces 534, 536. Aproximal sealing surface 534 is intended to seal against an insidedistal portion of the guide catheter 560 and a distal sealing surface isintended to seal against the inside of the blood vessel 550, for examplea coronary artery or an SVG. Although it is contemplated that theexpandable evacuation head 532 could include two balloon-type seals, forexample by adding a sealing balloon to each end of a tube 538 formingevacuation head 532, it is preferable to simply allow the outer surfaceof the expandable evacuation head 532 to create the sealing surfaces534, 536.

[0158] Preferably, evacuation tube 538 is formed of a braided sheath anda coating or covering over the braided sheath. The braided sheath itselfcan be made of stainless steel (full hard or spring), Eligiloy™, nickeltitanium alloy or other metals or polymers with high elasticitycharacteristics. Preferably the braided sheath which forms tube 538 hasa length of between about 3 cm and about 20 cm.

[0159] The braided sheath can be coated with a polymer such aspolyurethane, silicone and other similar elastomeric materials that canstretch and allow the braided sheath to expand. The covering or coatingis preferably a thin and flexible elastomer, which is dip coated on thebraided sheath. Since the elastomeric covering or coating is applied tothe braided sheath in its reduced dimension, the covering or coatinghelps to retain the braided sheath in its reduced dimension.

[0160] Alternatively, the braided sheath can be fitted with a fluidtight woven material that has similar expansion qualities as the braidedsheath. If the covering is a braided fabric, it is preferably made frompolyester or other high strength polymer yarn.

[0161] Alternatively, the covering may be formed of a spun fibers laiddown in multiple layers back and forth along the length of the braidedsheath. If the fiber layers are laid down at the same helical angle asthe primary braided sheath, the covering will behave similarly to theprimary braided sheath upon expansion, requiring little or no expansileforce to expand the covering from its reduced dimension to its expandeddimension. Each fiber layer will be made of several adjacent fiberwindings to create a dense layer. Preferably, there are multiple layers,which together will be relatively impervious to fluid flow, therebyallowing sealing surfaces of the evacuation head 532 to effectivelyisolate fluid communication from the lumen of the guide catheter withthe lumen of the blood vessel.

[0162] The braided sheath is preferably fabricated at its desiredreduced diameter, for example, as utilized in an SVG with an 8 Frenchguide catheter, about 0.4-1.5 mm. The braided sheath is then coated orcovered at this reduced size. The braided sheath which comprises theevacuation head 532 is preferably connected to an actuation wire 513 bya few of the filaments near the distal end of the braided sheath. Aproximal hollow shaft 511 is connected to a few of the braid filamentsnear a proximal end of the evacuation head 532 and serves as an anchorpoint. Actuation wire 513 sits within the hollow shaft 511 and thebraided sheath is preferably bonded or welded to the proximal hollowshaft 511 at the proximal end of the braided sheath and to the actuationwire 513 on the distal end of the braided sheath. The bonds attach in amanner that does not considerably impede the free movement of thebraided sheath during expansion and contraction.

[0163] The proximal hollow shaft 511 is a tube, which preferablydecreases in stiffness from a proximal end to a distal end thereof. Theproximal hollow shaft 511 can be made of stainless steel hypotubing,polyethylene, or a composite of polymers and metal.

[0164] Preferably, the evacuation head 532 includes a steerable springtip 544 extending from the actuation wire 513. Surrounding a portion ofthe spring tip 544 is a nose cone 543. The nose cone 543 serves as atapering transition between the spring tip 544 and a distal end of adelivery sheath 547. The nose cone 543 facilitates smooth advancement ofthe evacuation sheath assembly through a guide catheter 560 and into theblood vessel 550.

[0165] The delivery sheath 547 preferably comprises a tube which coversthe entire length of the reduced dimension of the evacuation head 532.The delivery sheath 547 is connected to a wire shaft (not shown), whichemerges from a proximal end of the guide catheter 560. Duringevacuation, the delivery sheath 547 may be fully removed from the lumenof the guide catheter 560, or can be left in position within the guidecatheter 560.

[0166] If the delivery sheath 547 is intended to be removed completelyfrom the guide catheter 560, it may include a perforated longitudinalline to allow for splitting of the delivery sheath 547 and removal ofthe delivery sheath 547 from the proximal hollow shaft 511 of theevacuation sheath assembly 500.

[0167] Alternatively, if the braided sheath has an expanded naturalshape and size as shown in FIG. 10C, thereby being self-expanding uponremoval of the delivery sheath 547, the delivery sheath 547 wouldpreferably be usable during contracting and removal of the braidedsheath. Thus, the delivery sheath 547 could be re-advanced to cover andconstrain the braided sheath once the procedure is completed. In thismanner, the evacuation sheath assembly 500 could be removed from theguide catheter 560.

[0168] The proximal end of the evacuation sheath assembly 500 may havean adjustable lock to anchor the actuation wire 513 to the proximalhollow shaft 511, allowing them to be held fixed to one another. Thisallows the braided sheath to be locked into a set position.

[0169] The evacuation sheath assembly 500, in use, is depicted in FIG.10D. Use of evacuation sheath assembly 500 is similar to the methoddescribed with respect to evacuation sheath assembly 100. Thedifferences between the method discussed with respect to FIGS. 6A-6I(evacuation sheath assembly 100) and that for evacuation sheath assembly500 are discussed below.

[0170] In use, a guide catheter 560 is advanced into blood vessel lumen550 over a guidewire 570. Evacuation sheath assembly 500, in acompressed state having a reduced diameter and enclosed in deliverysheath 547, is advanced through the lumen of guide catheter 560 overguidewire 570 and part way into blood vessel 550. Proper positioning ofa distal end of evacuation sheath assembly 500 is confirmed using, forexample, marker 545, nose cone 543, or by viewing the braided sheaththrough imaging.

[0171] After the positioning is verified, the delivery sheath 547 isremoved from the evacuation head 532. The actuation wire 513 is thenpulled proximally while the proximal hollow shaft 511 is heldstationary, preferably by a valve. Pulling the actuation wire 513proximally longitudinally compresses the braided sheath formingevacuation lumen 540, causing it to expand in diameter. The evacuationlumen 540 expands and the proximal sealing surface 534 of the evacuationhead 532 seals against the inside surface of the guide catheter 560. Theportion of the evacuation lumen 540 extending beyond the guide catheter560 and into the blood vessel 550 continues to expand until the distalsealing surface 536 of the evacuation head 532 seals against the insidesurface of the blood vessel 550. Similar to previous embodiments, theexpansion can be observed with fluoroscopy, and the blood pressure canbe monitored 592 until the waveform changes from pulsatile arterialpressure to a venous pressure (again, in the example of a coronary orSVG blood vessel).

[0172] With both seals in place, normal blood flow is stopped. Ifdesired, contrast dye may be injected through the catheter lumen intoblood vessel 550 to view blood vessel 550 prior to treating stenosis580. Stenosis 580 is then treated and any embolic debris is removed viaretrograde flow 590 (FIG. 10D) as previously described with respect toFIGS. 6C-6H. After treatment, the actuation wire 513 is re-advanced toallow the braided sheath to contract and be maintained in its reduceddimension prior to withdrawing the evacuation sheath assembly 500 fromblood vessel 550.

[0173] According to another aspect of the present invention, themulti-lumen tube forming the evacuation head may include three lumens.As embodied herein and shown in FIGS. 16A-16J, an evacuation sheathassembly 2100 is provided with an evacuation head 2132. Many of theelements present in the previous embodiments are also shown in FIGS.16A-16J and where these elements are substantially the same, similarreference numerals have been used and no detailed description of theelement has been provided.

[0174] As shown in FIGS. 16A and 16B, an evacuation sheath assembly 2100is provided with and includes an evacuation head and a shaft. Theevacuation head includes two expandable sealing surfaces on amulti-lumen tube. The evacuation sheath assembly is sized to fit withinand to be used with a guide catheter during the treatment of a vascularstenosis, e.g. within a coronary artery, such as a native coronaryartery or an SVG. For coronary-type applications, the evacuation headmay be between about 3 and 40 cm in length, and is preferably betweenabout 10 and 20 cm in length. In a most preferred embodiment, theevacuation head is about 15 cm in length. The total length of theevacuation sheath assembly 2100 for coronary applications, not includingany luer fittings, is preferably between about 110 cm and about 200 cm,and most preferably about 135 cm in length.

[0175] The evacuation head 2132 includes a multi-lumen tube 2138.Multi-lumen tube 2138 is preferably made of a relatively flexiblepolymer, for example, a polyester blend such as Hytrel 6356. Hytrel 6356has a relatively high melt temperature to facilitate subsequent heatbonding, as well as a relatively high lubricity and a relatively highflexibility. The multi-lumen tube 2138 preferably includes three lumensand has a circular cross-section. The outer diameter of the multi-lumentube is dependent upon the size of the guide catheters with which theevacuation sheath assembly 2100 is intended to be used. A presentlypreferred guide catheter is a size 8 French, a size readily availablefrom many manufacturers. To accommodate a size 8 French guide catheter,the multi-lumen tube 2138 preferably has an outer diameter of between0.065 and 0.080 inches, with an outer diameter of 0.072 inches beingmost preferred. Accommodation within a size 8 French guide catheterrequires the multi-lumen tube 2138 to have an inner diameter ID1 ofbetween 0.060 and 0.075 inches, and most preferably 0.067 inches (seeFIG. 16E). This results in a wall thickness of approximately 0.0025inches for the multi-lumen tube 2138, which varies dependent upon theinner and outer diameters of the multi-lumen tube 2138.

[0176] The first and preferably larger of the lumens, an evacuationlumen 2140, is designed to allow for the passage of interventionaldevices such as, but not limited to, stent delivery systems andangioplasty catheters. FIGS. 16E-16G most clearly show evacuation lumen2140. The evacuation lumen 2140 is also designed to allow for fluidflow, such as blood, blood/solid mixtures, radiographic dye and saline,within the evacuation lumen 2140. This flow of fluid may occurregardless of whether an interventional device is within the evacuationlumen 2140. The proximal end 2140 a of the evacuation lumen 2140 ispreferably angled to facilitate smooth passage of other therapeuticdevices through the evacuation lumen 2140 of the evacuation head 2132.

[0177] A second and preferably smaller lumen of the multi-lumen tube2138 is an inflation lumen 2142 having an open proximal end 2142 a and aclosed distal end 2142 b. FIGS. 16E-16G most clearly show inflationlumen 2142. The distal end 2142 b of the inflation lumen 2142 ispreferably closed with an adhesive, although other suitable materials,for example, thermal bonding, may be used to close the end 2142 b of thelumen 2142. The inflation lumen 2142 is designed to provide fluid toinflate balloons on the evacuation head 2132. The fluid may be eithergas or liquid in form, and is preferably a mixture of radiopaquecontrast media and saline.

[0178] The third lumen of the multi-lumen tube 2138 is also preferablysmaller than the evacuation lumen 2140 and forms a core wire lumen 2143,as most clearly shown in FIG. 16E. A core wire 2135 preferably extendsonly a portion of the length of the multi-lumen tube 2138, and istherefore not present within the core wire lumen 2143 of the distalportion of the multi-lumen tube 2138. The distal end of the core wirelumen 2143 is preferably closed with an adhesive, although othersuitable means such as thermal bonding may be used.

[0179] As shown in FIG. 16E, the inflation lumen 2142 and the core wirelumen 2143 are preferably positioned side-by-side against the inner wallof the multi-lumen tube 2138, and non-circular in cross section. As alsoshown in FIG. 16E, a wall separates the inflation lumen 2142 and thecore wire lumen 2143 from the evacuation lumen 2140. This separatingwall is preferably concave to the evacuation lumen 2140 and serves tomaximize the inner diameter ID2 of the evacuation lumen 2140 for devicepassage and fluid flow. The inner diameter ID2 of the evacuation lumen2140 is preferably between 0.053 and 0.068 inches, and most preferablyabout 0.060 inches.

[0180] As shown in FIGS. 16D-16H, the multi-lumen tube 2138 of theevacuation head 2132 incorporates a kink-resisting structure. A coil2139 can be wound directly onto the multi-lumen tube, expanded from awound state and slidingly placed over the multi-lumen tube or sized toslide onto the multi-lumen tube. Preferably, the coil 2139 is formed bya stainless steel ribbon of approximately 0.002 inches by approximately0.005 inches, with a pitch of approximately 0.010 inches. The innerdiameter of the coil 2139 should be approximately the same size as theouter diameter of the multi-lumen tube 2138. The final coil positionedadjacent to marker bands 2146 a and 2146 b (to be described later),producing a gradual stiffness transition to prevent kinking at theinterface between the coil 2139 and the marker bands 2146 a and 2146 b.A coating of polyurethane 2133 is then applied to contain the coil 2139,and secure it in position over the multi-lumen tube 2138 of evacuationhead 2132. The polyurethane may be applied by a solvent casting ofpolyurethane in an appropriate solvent. Alternatively, in a currentlypreferred method, the structure may be formed by applying a coating ofUV curable polyurethane, such as Dymax 204, between multi-lumentube/coil structure and a removable Teflon® sleeve. The combination isthen exposed to UV light and cured. The Teflon sleeve is then removedfrom the structure leaving a smooth coating surface 2133 thatencapsulates the coil 2139. The total thickness of the encapsulation ispreferably about 0.004 inches. To extend the length of the kinkresistant region of the evacuation head 2132, a second, shorter coil2139 a may be incorporated into the structure. The second coil 2139 a ispreferably positioned between the proximal marker band 2146 a and thesupport collar 2141, as shown in FIG. 16D. Use of the second coil 2139 aimproves bondability between the proximal waist 2134 a of the proximalballoon 2134 and the encapsulation layer 2133.

[0181] In addition to the encapsulation layer 2133, the UV curablepolyurethane is used to create a soft, beveled tip 2144 to the distalend of the multi-lumen tube 2138. The tip 2144 creates a taperedtransition to the distal ends of the core wire lumen 2142 and theinflation lumen 2143, reducing the tendency for embolic material tohang-up or get caught on the distal ends of the lumens. As shown inFIGS. 16A, 16B, 16F, and 16G, the distal end of the evacuation head 2132is perpendicular to a longitudinal axis of the evacuation lumen 2140 andproximate to a distal sealing balloon 2136. The perpendicular tip isuseful when the anatomy is such that an angled distal end would contactthe vessel wall in a way that would limit fluid flow through theevacuation lumen 2140.

[0182] As shown in FIG. 16D, the wall of the proximal end of themulti-lumen tube 2138 that defines the evacuation lumen 2140 ispreferably cut at an angle of between about 10 degrees and about 45degrees, and most preferably forming an angle of about 15 degrees withrespect to a longitudinal axis of the evacuation head 2132. This anglefacilitates smooth advancement of intravascular devices into theevacuation lumen and facilitates smooth removal of the evacuation head2132 from the guide catheter. The walls of the multi-lumen tube 2138which define the inflation lumen 2142 and the core wire lumen 2143 arenot cut at an angle, but instead extend proximally about 1 cm, tofacilitate attachment to an intermediate shaft of the evacuationassembly, to be described in detail later.

[0183] As embodied herein and shown in FIGS. 16D and 16J, the evacuationhead 2132 may include a structure to reinforce the proximal opening ofthe multi-lumen tube 2138. A support collar 2141 is positioned about theproximal end of the multi lumen tube 2138 and serves to reinforce theproximal opening of the evacuation lumen 2140 in the presence ofdeforming forces, particularly torsional stresses that may be createdunintentionally by rotation of the catheter shaft near its proximal end.As shown in FIG. 16J, the support collar 2141 includes a cylindricalportion 2141 a that fits into the proximal opening of the evacuationlumen 2140 and provides hoop support to the opening of the multi-lumentube 2138. The cylindrical portion 2141 a of the support collar 2141tapers into a tab portion 2141 b that extends proximally and in adirection parallel to a longitudinal axis of the evacuation lumen 2140.The tab portion 2141 b lies adjacent the exterior walls of themulti-lumen tube 2138 which define the core wire lumen 2143 and theinflation lumen 2142 and provides a flexibility transition between theproximal end of the evacuation head 2131 and the shaft of the evacuationsheath assembly 2100.

[0184] Preferably, the support collar 2141 is fabricated from a thinwalled metallic tube with a series of windows cut by suitable means suchas laser cutting, or electro-discharge machining (EDM). The windows 2141c allow for some flexibility and also allow for better adhesion of theencapsulation material 2133, which covers the support collar 2141, whilethe cylindrical portion 2141 a maintains hoop support to the proximalopening of the evacuation lumen 2140. In a preferred embodiment, thesupport collar 2141 has a wall thickness of approximately 0.002 inches,although it may vary between 0.001 and 0.004 inches. Preferably, thewidth of the tab portion 2141 b is between 0.020 and 0.050 inches, witha most preferred width of 0.038 inches. Although a metallic material ispreferred, any material with suitable rigidity to prevent kinking of thetab portion 2141 b of the collar 2141 with respect to the cylindricalportion 2141 a may be used.

[0185] The encapsulation 2133 formed over the exterior of themulti-lumen tube 2138 is formed with a reverse bevel 2125 at its extentover the proximal opening of the evacuation lumen, as shown in FIG. 16D.The reverse bevel 2125 is formed by curing UVPU that is wicked againstan inner diameter of a Teflon sleeve to impart the shape into theencapsulation 2133. The reverse bevel 2125 preferably is formed at anangle of between about 30 and 60 degrees from perpendicular and furtherserves to minimize hanging-up or catching of intravascular devices onthe proximal end of the evacuation head 2132. Stent delivery catheters,for example, are particularly subject to hanging-up on the proximal endof the evacuation head 2132 without reverse bevel 2125.

[0186] As shown herein and embodied in FIGS. 16A-16H, the evacuationhead 2132 includes two expandable sealing surfaces. A first proximalsealing balloon 2134 is configured to form a seal within the guidecatheter which delivers the evacuation sheath assembly 2100 to thesurgical site, as will be described. A second distal sealing balloon2136 is configured to form a seal within the blood vessel, as also willbe described.

[0187] As shown in FIGS. 16A and 16B, for a coronary application, it ispreferable that the distal sealing balloon 2136 be larger in size thanthe proximal sealing balloon 2134. The proximal balloon 2134 and thedistal balloon 2136 are in fluid communication with the inflation lumen2142 of evacuation head 2132. Inflation lumen 2142 is in fluidcommunication with a balloon inflation device 2199 (see FIG. 16I).

[0188] Preferably, the proximal and distal balloons 2134, 2136 areformed of a polymer such as polyurethane. Each sealing balloon 2134,2136 includes two waist portions, one proximal 2134 a, 2136 a and onedistal 2134 b, 2136 b of a body portion of the balloon. The waistportions 2134 a, 2134 b, 2136 a, 2136 b are preferably secured to anexterior of the multi-lumen tube 2138 using heat welding, solventbonding, or other suitable adhesive bonding techniques.

[0189] As shown in FIG. 16F, the waists 2136 a, 2136 b, of the distalballoon are external to the inflatable body of the balloon, i.e., theportions of the balloon attached to the multi-lumen tube 2138 extendaway from the inflatable portion of the balloon, rather than under theinflatable portion of the balloon. To minimize the distance between thedistal tip 2144 of the evacuation sheath assembly 2000 and the distalsealing balloon 2136, the distal waist 2136 b of the distal sealingballoon is relatively short, for example, approximately 2 mm.

[0190] Alternatively, to further minimize the distance between theballoon body and the distal tip 2144 of the evacuation sheath assembly2100, the distal waist 2136 b of the distal balloon 2136 may be“inverted” within the interior of the balloon, and secured to themulti-lumen tube 2138 as shown in FIG. 16G. In such an embodiment, thedistal tip may be eliminated, and a portion of the distal balloon 2136may extend beyond the distal end of the evacuation lumen 2140 to form asoft tip.

[0191] As embodied herein and shown in FIGS. 16A, 16B, 16F, and 16G, thedistal balloon 2136 may be characterized as being formed to include twocone portions, a proximal cone portion and a distal cone portion. Tofurther minimize the distance between the distal tip 2144 of theevacuation sheath assembly 2100 and an apex of the distal sealingballoon 2136, the length of the distal cone portion is kept relativelyshort by utilizing a relatively steep angle of between approximately 20degrees and approximately 45 degrees, and most preferably an angle ofapproximately 30 degrees, relative to a longitudinal axis of theevacuation head 2132. The proximal cone of the distal sealing balloon iskept at a relatively shallow angle, approximately 10 to approximately 20degrees, and most preferably approximately 15 degrees, relative to alongitudinal axis of the evacuation head 2132. Preferably, the angle isnot greater than approximately 30 degrees since it has been observedthat in blood vessels smaller than the initial expanded diameter of theballoon, resulting wrinkles in the balloon surface can prevent adequatesealing of the balloon against the blood vessel wall. The balloon body,i.e., the inflatable portion of the balloon, is relatively short,between approximately 0.1 and approximately 5.0 mm, and most preferablyapproximately 1 mm, in length. The balloon waists are secured to theencapsulation polymer 2133 surrounding multi-lumen tube 2138 by suitablemeans, preferably by thermal bonding of the waists 2136 a, 2136 b to theencapsulation polymer.

[0192] The distal sealing balloon 2136 is preferably blow molded from anextruded thermoplastic. A preferred material is polyurethane sold underthe trade name Pellethane 90AE. For coronary applications (includingSVG's), a preferred outer diameter after molding is about 5 mm, with aminimum wall thickness of about 0.0006 inch. These dimensionsaccommodate a range of vessel diameters of about 2.5 to 5 mm, whilerequiring relatively low balloon inflation pressures preferably nogreater than about 0.5 to 1 atmosphere, and preferably ⅔ atmosphere.

[0193] Adjacent the distal end of the coil 2139 is a distal marker band2146 b, for use in radiographic location of the distal balloon 2136. Ahole in the side wall of the distal marker band 2146 b is aligned with ahole in the wall of the multi-lumen tube 2138, defining a distalinflation port 2148 b. The distal inflation port 2148 b provides apathway for inflation fluid to fill the interior of the distal sealingballoon 2136. Positioning the distal inflation port 2148 b through theside wall of the distal marker band 2146 b eliminates the need for theinflation port 2148 b to extend through a widened pitch portion of thecoil 2139, potentially compromising the kink resistance of the coil2139.

[0194] The proximal sealing balloon 2134 is positioned near the proximalend of the evacuation head 2132. The proximal sealing balloon 2134 ispreferably blow molded from an extruded tube of a thermoplastic, such aspolyurethane, available under the trade name Pellethane 90AE. For a size8 French guide catheter, as described above, the expanded diameter ofthe proximal sealing balloon 2134 is between about 0.091 and about 0.99inches, and is most preferably about 0.094 inch, which allows forsealing with the same relatively low inflation pressures of the distalsealing balloon 2136, most preferably about ⅔ atmosphere. The proximalsealing balloon 2134 is preferably secured to the encapsulation polymer2133 surrounding multi-lumen tube 2138 by suitable means, preferably bythermal bonding of the waists 2134 a, 2134 b to the encapsulationpolymer.

[0195] A proximal marker band 2146 a, similar to the distal marker band2146 b, is positioned around the multi-lumen tube 2138, for use inradiographic location of the proximal sealing balloon 2134. As with thedistal marker band 2146 b, a hole in the side wall of the proximalmarker band 2146 a is aligned with a hole in the wall of the multi-lumentube 2138 to define a proximal inflation port 2148 a.

[0196] As shown in FIG. 16H, the inflation ports 2148 a, 2148 b includea first bore 2149 a drilled into the multi-lumen tube 2138 and a counterbore 2149 b drilled into the encapsulation material 2133. First, a holeof approximately 0.008 inches is drilled into the multi-lumen tube tocreate an opening into the inflation lumen 2142. Then, a larger diametercounter bore of approximately 0.025 inches is drilled into theencapsulation, increasing the area for the inflation fluid to exit theinflation lumen and enter into the sealing balloon. Both theencapsulation material 2133 and the material of the sealing balloons2134, 2136 tend to be tacky, causing adhesion problems between the twomaterials. The specific structure of the inflation ports permits easierinflation of the balloon at the desired low pressures.

[0197] According to another aspect of the invention, the evacuationsheath assembly 2100 includes a shaft. As embodied herein and shown inFIGS. 16A-16C, the shaft includes two sections, a proximal shaft portion2110 and an intermediate shaft portion 2120. The proximal shaft portion2110 preferably is formed from a metallic tube 2112 such as a stainlesssteel hypodermic tube. The proximal shaft portion 2110 preferably has aninner diameter ranging between approximately 0.010 and 0.025 inches,with a most preferred inner diameter of approximately 0.017 inches. Theproximal shaft portion 2110 preferably has an outer diameter rangingbetween approximately 0.015 and 0.030 inches, with an outer diameter ofapproximately 0.023 inches being most preferred. Preferably, themetallic tube 2112 is coated with a polymer sleeve or spray coating,such as PTFE, for lubricity.

[0198] The proximal shaft portion 2110 provides fluid communicationbetween an inflation apparatus (see FIG. 16I) and the intermediate shaftportion 2120. The proximal shaft portion 2110 may include markers (notshown) on its exterior surface. These markers are positioned to indicateto a user that the evacuation sheath assembly 2100 has been advancedthrough a guiding catheter 2160 (see FIG. 16I) to a location where thedistal end of the evacuation sheath assembly 2100 is just proximal tothe distal end of the guiding catheter 2160. The proximal shaft portion2110 is preferably secured to a luer hub 2105, for example by a weld oradhesive bond joint. The luer hub 2105 allows the evacuation sheathassembly 2100 to be connected to an inflation apparatus for theinflation of the sealing balloons 2134, 2136.

[0199] The intermediate shaft portion 2120 includes a tapered metalliccore wire 2135 inside a polymer tube 2122, as shown in FIG. 16C. Thecore wire 2135 is preferably stainless steel, about 0.015 inch diameter,tapering towards its distal end to about 0.008 inch. Alternatively, aspiral cut hypotube may replace the metallic core wire 2135. The polymertube 2122 is preferably fabricated from an extruded tube of high densitypolyethylene, preferably with an inner diameter of about 0.025 inchesand an outer diameter of about 0.032 inches. To facilitate attachmentbetween the evacuation head 2132 and the intermediate shaft portion2120, approximately 1 cm of a distal portion of polymer tube 2122 isflared and flattened by heating with an appropriately formed mandrel.This flared section is overlapped over the walls of the multi-lumen tube2138, which define the core wire lumen 2143 and the inflation lumen2142, as well as over the tab portion 2141 b of the support collar 2141.The distal portion of the core wire 2135 is inserted distally into thecore wire lumen 2143, and adhesively secured within the core wire lumen2143. Suitable adhesive such as cyanoacrylate or a UV curablepolyurethane adhesive is placed in the gap inside the flared end of thepolymer tube to secure it to the evacuation head 2132. To improve thebondability of the polymer tube 2122, particularly if fabricated of highdensity polyethylene, the inner surface of the tube may be modified byplasma treatment.

[0200] The proximal portion of the polymer tube 2122 is overlapped withthe distal portion of the metallic tube 2112 of the proximal shaftportion 2110 and bonded by suitable means such as an adhesive. Theproximal portion of the core wire 2135 is attached to the distal portionof the metallic tube by suitable means, preferably by spot-welding ofthe core wire 2135 to the inner surface of the metallic tube. Tominimize obstruction of the lumen of the metallic tube, the outerdiameter of the proximal end of the core wire 2135 is reduced,preferably to about 0.009 inch. Alternatively, the core wire may bepushed into a slotted hypotube. The inflation lumen 2142 is thus definedby the interior of the polymer tube and the metallic tube. A suitableconnector, such as a luer fitting 2105 and a strain relief tube, issecured to the proximal end of the metallic tube by suitable adhesivesuch as cyanoacrylate or UV curable polyurethane. The luer fittingfacilitates connection to an inflation apparatus.

[0201] In use, the evacuation sheath assembly 2100 is utilized with aguide catheter 2160, interventional devices including a guide wire 2170,an evacuation syringe, and an inflation apparatus 2199. A preferredset-up for a coronary application is illustrated in FIG. 16I.

[0202] The guide catheter 2160 is positioned in the patient usingconventional techniques. Connected to the proximal end of the guidecatheter is a three-arm adaptor 2185. The two proximal arms each includea conventional Touhy-Borst valve 2184, which includes a compression sealfor sealing around the exterior of guide wires, catheters, and the like.Various interventional devices, including a guide wire 2170 areintroduced through the first arm 2185 a. The evacuation sheath assembly2100 is introduced through the second arm 2185 b. In order to initiallyposition the guide wire 2170 through the evacuation lumen 2140, theevacuation sheath assembly 2100 is first partially introduced into thethree-arm adaptor 2185 such that the proximal end of the evacuationlumen 2140 is slightly distal of the first arm 2185 a. Then the guidewire 2170 is introduced into the evacuation lumen 2140, and to the endof the guide catheter 2160. (Procedures previously described withrespect to FIGS. 6A-6I, 13, 14, and 15 are applicable to this preferredembodiment of the evacuation sheath assembly 2100.)

[0203] By utilizing a separate arm 2185 b for the evacuation sheathassembly 2100, rather than introducing it through the same arm 2185 a asthe guide wire 2170, a robust seal can be obtained around the evacuationsheath assembly 2100, and around the guide wire 2170 and any additionalinterventional catheter such as a stent delivery catheter. If alldevices were introduced into a single arm with a single Touhy-Borstvalve, achieving a robust seal would be very difficult, particularlywhen using a “rapid-exchange” type of stent delivery catheter where thecatheter extends side-by-side with the guide wire. If the evacuationsheath assembly 2100 were to extend through the same Touhy-Borst valve,then the o-ring of the valve must seal against three devices, which canbe quite difficult. A typical Touhy-Borst valve can readily seal aroundone or two devices, but not three or more. It is important for use ofthe evacuation sheath assembly 2100 to establish robust seals, such thatwhen the evacuation steps are performed, there are no leaks through theTouhy-Borst valve(s).

[0204] A preferred inflation apparatus 2199 is shown connected to theevacuation sheath assembly 2100. The inflation apparatus 2199 is suitedto inflate the sealing balloons at a relatively low pressure. Theinflation apparatus 2199 includes a y-connector 2187. A pressure syringe2192 is connected to one arm of the y-connector 2187 and an inflationsyringe 2189 and two-way stopcock are connected to the other arm of they-connector 2187. The pressure syringe 2192 is an adaptation of aconventional syringe, utilizing a body and a plunger. Connected to theplunger is a spring, which compresses as pressurized fluid entering thesyringe pushes the plunger. A scale on the body corresponds to pressure,and as such, the pressure syringe serves as a pressure gauge.

[0205] In use, the inflation syringe 2189 of the inflation apparatus2199 is filled with fluid such as a mixture of saline and radiographicdye. It is then connected to the evacuation sheath assembly 2100. Toinflate the sealing balloons of the evacuation sheath assembly 2100,fluid from the inflation syringe 2189 is injected into the evacuationsheath assembly 2100 to a pressure of between ½ and 1 atmosphere, andpreferably to about ⅔ of an atmosphere. The two-way stopcock is closed,and the pressure syringe 2192 then maintains a steady ⅔ of an atmospherepressure on the sealing balloons 2134, 2136. The preferred pressure hasbeen determined to be adequate for sealing purposes, yet low enough toprevent vascular injury.

[0206] The evacuation syringe 2188 and contrast line 2188 a arepreferably connected to the third arm 2185 c of the three-arm adaptor,via a standard 3-way stopcock. The third arm 2185 c of the three armadaptor 2185 is distal to the first and second arms 2185 a, 2185 b ofthe adaptor as shown in FIG. 16I. The third arm 2185 c preferablyconnects to the three-arm adaptor 2185 at a location distal of theconnection of the first arm 2185 a and the second arm 2185 b to thethree-arm adaptor 2185, preferably between about 0.5 and 1.5 cm distalof these arms. This positioning serves to help prevent particulate frombecoming trapped in the first or second arms during evacuation. If thethird arm was connected proximate to the first and second arms of thethree-arm adaptor, particulate might gather where the shaft of theevacuation sheath assembly crosses the guide wire, creating a risk ofsubsequent injection that particulate back into the vasculature. Thispreferred embodiment moves the arm 2185 c connected to the evacuationsyringe 2188 distal of the area where the shaft and guide wire cross, toa position where the guide wire and shaft are parallel. Thus, noparticulate should get caught between the guide wire and shaft beforebeing evacuated by the evacuation syringe. Due to the specificarrangement of the arms where the arm 2185 c is distal to the first andsecond arms 2185 a, 2185 b, the particulate will tend to flow directlythrough the third arm 2185 c and into the evacuation syringe before itcan reach the first arm 2185 a and/or second arm 2185 b. Furthermore,should any particulate become lodged in or near the first arm 2185 aand/or second arm 2185 b, any subsequent contrast injections (whichwould also be via the third arm 2185 c), will not re-inject the trappedparticulate.

[0207] The method of use of the evacuation sheath assembly 2100 isessentially the same as that described with respect to FIGS. 6A-6I, withthe exception of the use of the three arm adaptor 2185, as describedabove. As also mentioned above, methods discussed with respect to FIGS.13-15 are also applicable to evacuation sheath assembly 2100.

[0208] The evacuation sheath assemblies 100, 200, 300, 400, 500, and2100 previously described may encounter difficulty in traversingtortuous anatomy due to their relatively large diameter. FIG. 11E showsan obturator assembly 900 that is designed to be used with thepreviously described evacuation sheath assembly 100, or with othersheath assemblies described later herein, particularly those withrespect to FIGS. 1A, 1C, and 3A. Use of the evacuation sheath assembly100 with obturator assembly 900 is illustrated in FIG. 11G. Theobturator assembly 900, when placed within the evacuation sheathassembly 100, provides a tip 920 of obturator assembly 900 which extendsbeyond the evacuation sheath assembly 100. The tip 920 is preferablyless stiff and smaller in diameter than the evacuation sheath assembly100, and provides a gradual diameter and stiffness transition to thelarger evacuation sheath assembly 100. This design allows the operatorto traverse tortuous anatomy more easily than without the obturatorassembly 900. The tip 920 may also be formable to allow the operator tobend the tip 920 for steering in blood vessels. The operator directs tip920 by applying a torque to the proximal end 900 a of the obturatorassembly 900.

[0209] The obturator assembly 900 is preferably made of a polymer orpolymer-metal composite material, but other biocompatible materialshaving suitable flexibility characteristics may be used. As shown, onlya distal portion 900 b has an enlarged diameter. Alternatively, theentire length of obturator assembly 900 could have a uniform diameter.The diameter of the enlarged distal portion 900 b is relatively close toan inside dimension of the evaluation lumen 140 of evacuation sheathassembly 100. The obturator assembly 900 has a guide wire lumen 930 witha proximal end 930 a and a distal end 930 b. The proximal end 930 a ofguide wire lumen 930 is preferably located distally of the proximal end900 a of the obturator assembly 900. The guide wire lumen 930 isdesigned to allow for the passage of a guide wire. A fluid source (notshown) may be connected to a luer fitting 940. An infusion lumen 910allows for the flow of fluid from a fluid source through a proximal end910 a to a distal end 910 b of the lumen 910. Fluids may includeradiopaque dye, heparin/saline mixture, or blood. A radiopaque markerband 950 is located at the end of tip 920 to allow the operator tovisualize the tip of the obturator assembly 900 during angiography. FIG.11F is a cross-sectional view of the obturator assembly 900 shown inFIG. 11E.

[0210] Alternatively, the obturator assembly may be constructed as aballoon catheter. FIG. 11H illustrates an embodiment of a balloonobturator assembly 1000. The balloon obturator assembly 1000 has acatheter shaft 1015 that is preferably made of a polymer or a polymermetal composite, or other biocompatible material having suitableflexibility characteristics. The catheter shaft 1015 includes proximaland distal shaft portions 1015 a and 1015 b, respectively.

[0211] The balloon obturator assembly 1000 includes a guide wire lumen1030 for passing a guide wire through. The guide wire lumen 1030 has aproximal end 1030 a and a distal end 1030 b. Proximal end 1030 a ispreferably located distally of the proximal end 1000 a of the balloonobturator assembly 1000. The balloon obturator assembly 1000 alsoincludes an inflation lumen 1070, which allows fluid flow between afluid source (not shown) connected to a luer fitting 1060 and a balloon1090. The fluid passes through an inflation port 1080 to inflate balloon1090.

[0212] The balloon obturator assembly 1000 may also include an infusionlumen 1040. A proximal end 1040 a of infusion lumen 1040 has a sealedconnection to a luer fitting 1045. Luer fitting 1045 may be connected toa fluid source (not shown). The fluid source contains a fluid such asradiopaque dye, heparin/saline mixture, or blood. The infusion lumen1040 allows for fluid flow between the fluid source and the distal end1040 b of the infusion lumen 1040, where the fluid exits the infusionlumen 1040 through infusion port(s) 1050. A radiopaque marker band 1010is preferably attached to distal tip 1000 b of the balloon obturatorassembly 1000. This allows the operator to visualize the location of theballoon obturator assembly 1000 during angiographic procedures. FIG. 11Iand FIG. 11J are cross-sectional views of the balloon obturator assemblyFIG. 11H taken along lines A-A and B-B, respectively.

[0213]FIG. 11K shows the balloon obturator assembly 1000 positioned in apreviously described evacuation sheath assembly 100 as it would be usedin the blood vessel 150. The balloon 1090 is inflated against theevacuation lumen 140 to secure the balloon obturator assembly 1000 tothe evacuation sheath assembly 100 during use. In this position, theballoon obturator assembly 1000 provides a gradual diameter transitionfrom the distal guide wire lumen 1030 b, to the distal end of theevacuation sheath assembly 100. The balloon obturator assembly 1000 isdesigned to be deflated and removed from the blood vessel 150 after theevacuation sheath assembly 100 has been properly located in the bloodvessel.

[0214] Additionally, the balloon obturator assembly 1000 may be advanceddistal to the evacuation sheath assembly 100 to a treatment site. Theballoon 1090 of the balloon obturator assembly 1000 may then be inflatedto pre-dilate the treatment site. Pre-dilatation will allow subsequenttreatment devices to traverse the treatment site more easily.Additionally, the balloon obturator assembly 1000 can provide infusionfluids to a location distal of the treatment site through the infusionport(s) 1050. The infusion of fluid can be done with the balloon 1090inflated or deflated. The infusion of fluids provides fluids distal tothe treatment site and also provides a fluid for particulate removal, aswill be described later in conjunction with other embodiments ofinfusion catheters.

[0215] In use, the evacuation sheath assemblies 100, 200, 300, 400, 500,and 2100 discussed previously may experience slow or limited retrogradeflow in certain vascular anatomies of some patients. This limitation maycause incomplete removal of debris from the blood vessel. In coronaryapplications of the invention, flow may be limited by the lack ofcollateral vessels that connect to the vessel being treated or becauseof the inability of the coronary venous system to supply fluid flowrates capable of retrograde removal of the debris, due, for example, tothe presence of one-way valve structures in the coronary veins. Whenthis anatomy is present, aspiration of the evacuation sheath assembly(as represented by assembly 100 as described in connection with FIGS.1A, 5A, and 6G) results in a short surge of retrograde movement of theblood in the vessel, followed by a very slow continuous retrograde flow.Methods for removing remaining particulate under slow retrograde flowconditions are described below. These methods are described with respectto the evacuation sheath assembly 100 and method of use of evacuationsheath assembly 100 previously described in conjunction with FIGS.6A-6I. However, these methods can be utilized in conjunction with any ofthe evacuation sheath assemblies and methods of use previously describedherein.

[0216] While much of the particulate will move retrograde (proximal) ofthe lesion site after the initial short surge of flow and actually enterinto the distal end 140 b of the evacuation lumen 140, some of theparticulate 197 may remain within the blood vessel lumen 150.Furthermore, the relatively slow flow rate which follows the initialsurge in, for example, the types of anatomy mentioned in the priorparagraph, may not be sufficient to urge the particulate 197 into theevacuation lumen 140, and may also not be sufficient to carry theparticulate 197 to the proximal end 140 a of the evacuation lumen 140,into the guide catheter, and then into the collection chamber 188.

[0217] When flow limiting anatomy is present, an alternative method maybe utilized to carry the particulate 197 from the lesion site, into andcompletely through the evacuation lumen 140. Referring to the point inthe procedure shown in FIG. 6G, aspiration is applied to the evacuationlumen 140, which causes an initial surge of retrograde flow 195.Continued application of a vacuum to the evacuation lumen 140, in spiteof slow flow, may successfully remove all the particulate 197 from thevessel 150 and from the evacuation lumen 140. However, it is preferredto release the vacuum after the initial retrograde surge, by turning offthe stopcock to the vacuum source 188. This allows for the lumen 150 ofthe artery, which is still under a reduced pressure (and likely under anegative pressure), to slowly refill and re-pressurize from the venouscirculation. After a few seconds, the vacuum is re-applied to theevacuation lumen 140, causing a second retrograde surge of fluidcarrying particulate 197 from the lumen 150 of the artery. Thistechnique can be repeated as needed until all of the particulate 197 iswithdrawn fully into the evacuation lumen 140. The repeated retrogradesurges help assure that the particulate 197 passes into the evacuationlumen 140.

[0218] After the appropriate number of cycles of retrograde surges havebeen performed, the sealing balloons 134, 136 are deflated while avacuum is applied to evacuation lumen 140, which creates vigorousretrograde flow 195 in the evacuation lumen 140 by drawing arterialblood from the aorta. After all the particulate 197 is transported intothe collection chamber 188, the vacuum is turned off.

[0219] While the above technique is described in connection with theembodiments shown in FIGS. 1A, 5A, and 6G, it is to be understood thatthis technique could be adapted to other embodiments of the invention,as well as to other parts of the anatomy.

[0220] Another method may be employed in anatomical situations wherelimited retrograde flow is experienced during use of any one of theevacuation sheath assemblies described herein, for example evacuationsheath assembly 100 in a coronary application (SVG or native). FIG. 15illustrates the posterior side of the heart, showing the venouscirculation. The coronary veins 2000 drain into the coronary sinus 2010and into the right atrium 2020. The superior vena cava 2030 and inferiorvena cava 2040 also drain into the right atrium 2020.

[0221] One of the contributors to slow retrograde flow during use of theevacuation sheath assembly 100 (as described previously) is the presenceof valves 2045 in the coronary veins 2000 and sinus 2010. These valves2045, when present, are typically found at the coronary sinus ostium, aswell as at the ostia of the veins at the coronary sinus 2010. Thesevalves 2045 close when flow in the veins is reversed, and venouspressure is reduced. Valve closure can be avoided if the pressure withinthe coronary sinus 2010 and veins 2000 can be maintained at an elevatedlevel. The elevated pressure causes dilation of the sinus 2010 and veins2000, which prevents full closure of the valves 2045 in the presence ofretrograde flow. Therefore, if retrograde flow is induced in theevacuation sheath assembly 100, this flow will draw from the venouscirculation as long as the valves 2045 in the venous circulation areprevented from closing.

[0222] To maintain an elevated pressure in the coronary sinus 2010, acoronary sinus occlusion catheter 2050 is employed. The occlusioncatheter 2050 may be delivered into the femoral vein, and into the rightatrium 2020 via the inferior vena cava 2040. The occlusion catheter 2050may include a pre-formed shape 2060 to facilitate introduction into thecoronary sinus 2010 and advancement over a guide wire. Alternatively,the occlusion catheter 2050 can be delivered with the assistance of aseparate shaped guiding catheter, as is known in the art. Angiographicimaging techniques may be used in the placement of the occlusioncatheter 2050. Another alternative is to deliver the occlusion catheter2050 from a superior location via the subclavian or jugular vein, andinto the right atrium 2020 via the superior vena cava 2030.

[0223] As illustrated in FIG. 15, the occlusion catheter 2050incorporates an occluding element 2070 which is preferably an expandableballoon. A lumen (not shown) extends through the shaft of the occlusioncatheter 2050, to allow for continuous pressure monitoring. In use, theocclusion catheter 2050 is placed at any time prior to deflation of thestent balloon 193 (FIG. 6G) and preferably placed just prior toinflation of balloons 134, 136 to stop antegrade flow (FIG. 6C). Theballoon 2070 is inflated until the coronary sinus pressure increasesenough to prevent closure of the venous valves 2045. The pressure ismonitored and the balloon size adjusted accordingly. The stepspreviously described in connection with FIGS. 6C-6I may then beperformed. After the procedure is complete, the occlusion catheter 2050is removed.

[0224] Another alternative method of removing embolic debris in thistype of anatomy (which results in slow retrograde flow) is provided. Thesteps necessary to remove embolic debris 197 from a vessel 150 areessentially identical to the steps as previously described with respectto FIGS. 6A-6G. The following steps allow for the complete removal ofdebris 197 if slow or limited retrograde flow is experienced.

[0225] In this method, interventional balloon 193 a of interventionaldevice 193 occludes distal flow and aortic blood provides the flownecessary for the retrograde removal of debris 197. To begin, theintervention balloon 193 a is deflated after positioning the stent (FIG.6G), and the debris 197 is moved to a position retrograde (proximal) ofthe treatment site, due to the initial short surge of retrograde bloodflow, which is followed by relatively stagnant or slow retrograde flow.The retrograde flow is then stopped by releasing the vacuum applied tothe evacuation lumen 140.

[0226] The balloon 193 a of the stent delivery catheter 193 is thenre-inflated within the stent site 194. As shown in FIG. 13, whileintervention balloon 193 a is inflated, a vacuum is applied to the guidecatheter 160, and the proximal and distal sealing balloons 134, 136 aredeflated, allowing blood from the aorta 191 to flow into the vessel 150and past the end of evacuation sheath assembly 100. Preferably for thismethod, the guide catheter 160 and evacuation head 132 are sized suchthat retrograde flow of blood entering into the lumen of the guidecatheter 160 enters primarily via the lumen 140 of the evacuation head132, and not directly into the distal end of the guide catheter 160.This blood flow 191 is then caught by the flow reversal caused by thevacuum applied to the guide catheter 160, and reverses into theevacuation sheath.

[0227] The meeting of the aortic blood flow 191 and the reverse flow 195causes a turbulent flow 196 in the fluid distal of the evacuation sheathassembly 100. The reversing flow causes the debris 197 to flow withretrograde fluid flow 195 into the evacuation head 132, removing thedebris 197 from the vessel 150. The turbulent flow 196 extends distallyof the distal tip of the evacuation sheath assembly 100, effectivelycapturing particulate 197 which may be significantly distal of theevacuation sheath assembly 100. It is preferable, however, to have theevacuation sheath assembly 100 close enough to the lesion 180 tomaximize the particulate 197 captured. Preferably this distance is lessthan about 10 cm.

[0228] Next, the vacuum is released, the balloon 193 a of stent deliverycatheter 193 is deflated, and flow of blood in the antegrade direction190 is re-established. The stent delivery catheter 193 is then removedfrom the vessel 150. While the above description is made with respect tothe therapeutic catheter being a stent delivery catheter, othercatheters may be employed as well, as long as they are able to occludeantegrade flow through the lesion during the aspiration step.

[0229] According to another aspect of the present invention, theevacuation sheath assemblies 100, 200, 300, 400, 500 described earliermay be used in conjunction with an infusion catheter to supply fluidflow when slow or limited retrograde flow is experienced. FIGS. 12A-12Mshow several variations of an infusion catheter assembly.

[0230] FIGS. 12A-12C illustrate an embodiment of infusion catheterassembly. Infusion catheter assembly 600 includes a distal shaft 690,which is preferably a multi-lumen tube. The distal shaft 690 ispreferably made of a flexible polymer such as polyethylene, Pebax®, orHytrel®. Alternatively, the distal shaft 690 can be made of a compositepolymer and metal material or from other suitable biocompatiblematerials exhibiting, for example, appropriate flexibility.

[0231] The infusion catheter assembly 600 includes a luer fitting 660which creates a sealed connection between the infusion catheter assembly600 and a fluid source (not shown). The luer fitting 660 is connected toa proximal shaft 670, which is preferably made of a metallic material oralternatively of a metal polymer composite or other suitablebiocompatible material. The proximal shaft 670 includes a proximalinfusion lumen 640 a and preferably extends to a position just proximalto a proximal end 630 a of a guide wire lumen 630.

[0232] Preferably, the proximal shaft 670 includes proximal shaftmarkers 620 that provide a structure for determining when the catheterhas been advanced to a location just proximal to the distal tip of theevacuation sheath assembly.

[0233] The distal shaft 690 includes two lumens. A distal infusion lumen640 b is designed to allow for fluid flow, such as saline,heparin/saline mixtures or radiographic dye, from the fluid source andproximal infusion lumen 640 through the distal infusion lumen 640 b. Aguide wire lumen 630 is designed to allow for the passage of a guidewire. The guide wire lumen 630 has proximal and distal ends 630 a, 630b. The proximal end 630 a is positioned distal of the proximal end 600 aof the infusion catheter assembly 600. The distal end of the distalshaft 690 is tapered to allow easy passage of the assembly 600 through ablood vessel. Additionally, a radiopaque marker 610 is attached near thedistal end of the distal shaft 690 to allow the operator to visualizethe infusion catheter assembly 600 by fluorscopy.

[0234] Additionally, the distal infusion lumen 640 b communicates with amultitude of infusion ports 650, which are preferably disposed radiallyabout the distal region of distal infusion lumen 640 b and located lessthan 80 mm, preferably less than 40 mm, and more preferably less than 20mm from the distal tip. Alternatively and/or additionally, ports may beprovided longitudinally along a distal end 640 c of the distal infusionlumen 640 b. The infusion ports 650 are designed to allow for fluid flowfrom the proximal infusion lumen 640 a to distal infusion lumen 640 b toexit the infusion catheter assembly 600.

[0235] An alternative construction of a distal shaft 690 is shown inFIGS. 12D-12F. In this construction, a single infusion port 650 islocated at the distal end 640 c of the distal infusion lumen 640 b.

[0236]FIGS. 12G and 12H show a further alternative infusion catheterassembly 700. The infusion catheter assembly 700 includes aninfusion/guide wire lumen 740 having a proximal end 740 a and a distalend 740 b. Infusion/guide wire lumen 740 is contained within an infusioncatheter shaft 770 having a proximal end 755 a and a distal end 755 b,which allows for the passage of a guide wire. The infusion/guide wirelumen 740 is also designed to allow for fluid flow within theinfusion/guide wire lumen 740. This fluid flow may occur regardless ofwhether a guide wire is within the infusion/guide wire lumen 740. Theinfusion catheter shaft 770 is preferably made of polyethylene.Alternatively, the infusion catheter shaft 770 may be constructed ofother polymers, polymer and metal composites, or other suitablebiocompatible materials.

[0237] A luer fitting 760 is attached to the proximal end 740 a of theinfusion catheter shaft 770. The luer fitting 760 creates a sealedconnection between the infusion catheter assembly 700 and a fluid source(not shown). Luer fitting 760 may also include a hemostatic valve 765 toseal around a guide wire placed within the infusion/guide wire lumen740. Infusion catheter shaft 770 preferably includes proximal markerbands 720 to provide a structure for determining when the catheter hasbeen advanced to a location just proximal to the distal tip of theevacuation sheath. Preferably, a radiopaque distal marker 710 is locatedabout the distal tip 755 b of the infusion sheath shaft 770. Distalmarker 710 provides visualization of the infusion sheath shaft 770 tipunder fluoroscopy.

[0238] A further alternative construction of an infusion catheter 700 isshown in FIGS. 12I and 12J. This construction is similar to that of FIG.12G, except that the catheter 700 of FIGS. 12I and 12J has a reduceddiameter at its distal end 755 b. The reduced diameter of distal end 755b is designed to make the infusion catheter 700 track more easily intortuous vessel anatomies. Fluid flow within the infusion/guide wirelumen 740 exits the infusion sheath shaft 770 at the distal end 755 b.Fluid flow is allowable when a guide wire is present or not presentwithin the infusion/guide wire lumen 740. Fluid flow is improved withinthe infusion/guide wire lumen 740 when the guide wire is retractedproximally of the reduced diameter region of the infusion/guide wirelumen 740.

[0239] An alternative to the catheter 700 of FIG. 12I is shown in FIGS.12K and 12L. Catheter 700 of FIGS. 12K and 12L also includes a multitudeof infusion ports 750, that are preferably disposed radially about thedistal end 740 b of the infusion/guide wire lumen 740. The infusionports 750 are preferably located a relatively short distance from thedistal end 755 b of infusion catheter 700. Fluid flow is within theinfusion/guide wire lumen 740. This fluid flow may occur regardless ofwhether a guide wire is within the infusion/guide wire lumen 740 andextends distal of the distal end 755 b.

[0240]FIGS. 12M and 12N show another infusion catheter assembly 800. Theinfusion catheter assembly 800 includes a proximal infusion lumen 840 acontained within a proximal shaft 870. The proximal infusion lumen 840 ais designed to allow for fluid flow between a fluid source (not shown)and a distal infusion lumen 840 b. The infusion catheter assembly 800preferably does not contain a guide wire lumen, and is delivered withinthe vessel lumen without being tracked over the indwelling guide wire.

[0241] The infusion catheter assembly 800 has a luer fitting 860 thatcreates a sealed connection between the infusion catheter assembly 800and a fluid source (not shown). The luer fitting 860 is connected to theproximal shaft 870, which is preferably made of a metallic material oralternatively a metal polymer composite, or other suitable biocompatiblematerial. The proximal shaft 870 contains proximal infusion lumen 840 aand extends to be overlapped by a distal shaft 890. Proximal shaft 870and distal shaft 890 connect by an overlapping joint or other suitableconnection means.

[0242] Additionally, a stiffness transition member 880 is attached to adistal end 870 b of the proximal shaft 870. The stiffness transitionmember 880, preferably made of stainless steel or alternatively of othermetals or composites, extends within the infusion lumen 840 b of thedistal shaft 890. The stiffness transition member 880 preferably has astiffness that decreases along its length from its proximal end 880 a toits distal end 880 b. The decrease in stiffness is attributed to areduction in the cross sectional area of the member 880. The stiffnesstransition member 880 is preferably sealingly bonded to the distal end890 b of the distal shaft 890 and may extend distally beyond the bond.The portion of the stiffness transition member 880 that extends beyondthe distal shaft 890 is surrounded by and fixed to a spring coil 815.The spring coil 815 is preferably made of platinum or another metal of adensity suitable for visualization by fluoroscopy. The stiffnesstransition member 880 and the spring coil 815 assembly can be bent intoa predetermined shape. The predetermined shape is designed to help steerthe assembly 800 through turns in the blood vessel, without the need fortracking over the indwelling guide wire. Alternately, there may be nodistally extending spring coil 815. Preferably, the proximal shaft 870contains proximal shaft markers 820, providing a structure fordetermining when the catheter has been advanced to a location justproximal to the distal tip of the evacuation sheath.

[0243] Additionally, the distal infusion lumen 840 b may include amultitude of infusion ports 850 that are preferably disposed radiallyabout the distal infusion lumen 840 b. The infusion ports 850 aredesigned to allow for fluid flow from the infusion lumen 840 to exit theinfusion catheter assembly 800.

[0244] FIGS. 17A-17D show an alternative infusion catheter assembly1500. The infusion catheter assembly 1500 is a preferred embodiment foruse in coronary-type applications. The infusion catheter assembly 1500includes a shaft that has three portions, a distal shaft portion 1590,an intermediate shaft portion 1580, and a proximal shaft portion 1570.

[0245] The distal shaft portion 1590 includes two lumens. As shown inFIG. 17D and embodied herein, the distal shaft portion 1590 includes aninfusion lumen 1540 and a guide wire lumen 1530. Preferably, the distalshaft portion is fabricated from an extruded dual lumen tube made of alubricious and flexible polymer, for example, high density polyethylene.The dual lumen tube preferably has cross-section with a “figure 8”configuration. Such a configuration, when present within the evacuationlumen of an evacuation sheath assembly, maximizes the available lumenspace for fluid and particulate flow. The infusion lumen 1540 includes amarker band 1510 positioned near the distal end 1540 b of the infusionlumen 1540 to allow the operator to visualize the infusion catheterassembly 1500 by fluoroscopy. The distal end 1540 b of the infusionlumen 1540 terminates in a single infusion port 1550. The infusion port1550 is designed to allow for fluid flow from a fluid source, throughthe shaft of the infusion catheter assembly, to exit the infusioncatheter assembly 1500. Additional side ports in the tubing wall (notshown) may also be provided. The distal end 1540 b of the infusion lumen1540 is preferably beveled (see FIG. 17A) to facilitate advancement intoa Touhy-Borst valve (not shown) through which a guide wire extends.

[0246] The guide wire lumen 1530 is preferably between about 3 and 20 cmin length, and is most preferably about 6 cm in length. The proximal end1530 a of the guide wire lumen 1530 is preferably beveled to facilitatewithdrawal from the Touhy-Borst valve.

[0247] The intermediate shaft portion 1580 includes a proximal linearlyextending polymer tube 1580 a and a distal linearly extending polymertube 1580 b adjacent the proximal tube. The intermediate shaft portion1580 also includes an internal core wire 1535, as shown in FIG. 17C. Thecore wire 1535 extends distally into the distal shaft portion 1590, andterminates at the marker band 1510. The distal polymer tube 1580 b ispreferably a single lumen extrusion and is preferably made from highdensity polyethylene. The distal tube 1580 b is joined to the walls ofthe tube which define the infusion lumen 1540 of the distal shaftportion 1590. The proximal polymer tube 1580 a is preferably larger indiameter than the distal tube 1580 b and is also preferably formed ofhigh density polyethylene. The proximal tube 1580 a is secured to thedistal polymer tube 1580 b by suitable means, such as an adhesive orthermal bonding.

[0248] The proximal shaft portion 1570 includes an extension of thepolymeric proximal tube 1580 a of the intermediate shaft portion 1580.Inside the proximal tube 1580 a is a spiral cut hypotube of stainlesssteel 1575. The cross section of this shaft portion 1570 is shown inFIG. 17B. The core wire 1535 of the intermediate shaft portion 1580 isconnected to a distal end of the spiral cut hypotube 1575, preferably byspot welding. The spiral cut hypotubing 1575 serves to prevent collapseof the proximal shaft portion 1570 when pressure is applied by thetightened Touhy-Borst valve (not shown). The length of the proximalshaft portion, not including a luer fitting 1505 or a strain relieftubing 1507, is preferably between about 40 and 50 cm, and the proximalshaft portion most preferably is about 46 cm in length. The length ofthe proximal shaft portion 1570 should be sufficient to ensure that atleast a portion of the spiral cut hypotubing is within the Touhy-Borstvalve when the distal end of the infusion catheter assembly 1500 iswithin the coronary vessel. In addition, the length of the proximalshaft portion 1570 should be short enough to minimize the flowresistance imparted by the spiral cut hypotube.

[0249] As shown in FIG. 17A, a luer fitting 1505 and a strain relieftube 1507 are connected to the proximal shaft section by suitable means,preferably adhesive bonding.

[0250] In use, the evacuation sheath assemblies discussed previouslymay, as also noted previously, experience slow or limited retrogradeflow. When this condition is present, use of one of the embodiments ofinfusion catheter assembly described above may be used to facilitateremoval of embolic material. FIG. 14 illustrates the use of an infusioncatheter assembly, together with an evacuation sheath assembly 100. Amethod for removing particulate under slow retrograde flow conditions isdescribed below. This method is described with respect to the evacuationsheath assembly 100 and method of use of evacuation sheath assembly 100previously described in conjunction with FIGS. 6A-6I. However, thismethod can be utilized with any of the evacuation sheath assemblies andmethods of use previously described herein.

[0251] The steps necessary to remove embolic debris 197 from vessel 150are essentially identical to the steps described previously with respectto FIGS. 6A-6G. Flow may be limited by the lack of collateral vesselsthat connect to the vessel being treated, because of the inability ofthe coronary venous system to supply fluid flow rates capable ofretrograde removal of the debris, or for other reasons. The presentmethod was developed to utilize an infusion catheter assembly 600, 700,800, 1500 to provide the fluid flow necessary for the retrograde removalof debris 197. As shown in FIG. 14, the infusion catheter assembly isrepresented by reference numeral 175, however, any one of the infusioncatheter assemblies previously described herein may be used.

[0252] After the debris has been moved retrograde (proximal) of thetreatment site, the stent delivery catheter 193 is withdrawn from theblood vessel. FIG. 14 shows the distal end of the infusion catheterassembly 175 advanced beyond the treatment site. A vacuum is thenapplied to the guide catheter 160. A fluid 176, such as saline,heparinized saline, whole blood (drawn, for example, from theipsilateral or contralateral femoral artery) and/or radiopaque dye, isthen injected through the infusion catheter assembly 175 emerging fromthe infusion catheter assembly through infusion ports 178. The vacuumapplied to the guide catheter 160 induces retrograde flow 195 in thefluid distal to the treatment site and proximate to the ports 178 of theinfusion catheter assembly 175. The reversing flow causes the debris toflow with the retrograde flow 195 into the evacuation head 132, removingthe debris 197 from the vessel.

[0253] As long as the ports 178 of the infusion catheter assembly 175are positioned distally of the treatment site, it is not important thatinflow of infused fluid be matched to outflow of fluid removed throughthe evacuation sheath assembly 100. In fact, it may be preferable toinfuse fluid at a higher volumetric flow rate than what is evacuated. Inthis manner, the blood vessel 150 will not be exposed to negativepressures, which may tend to collapse the blood vessel 150 and preventegress of fluid and particulate.

[0254] Other embodiments of the invention will be apparent to thoseskilled in the art from consideration of the specification and practiceof the invention disclosed herein. It is intended that the specificationand examples be considered as exemplary only, with a true scope andspirit of the invention being indicated by the following claims.

What is claimed is:
 1. An evacuation sheath assembly, comprising: a tubehaving three lumens and first and second sealing surfaces, wherein afirst lumen is an evacuation lumen configured to be placed in fluidcommunication with a bloodstream, wherein a second lumen is an inflationlumen in fluid communication with at least one of the first and secondsealing surfaces, and wherein a third lumen is a core wire lumen; and ashaft in fluid communication with the inflation lumen and configured toconnect to an inflation source.
 2. The assembly of claim 1, wherein thefirst and second sealing surfaces are balloons.
 3. The assembly of claim1, wherein the first sealing surface is located on a proximal portion ofthe tube and the second sealing surface is located on a distal portionof the tube.
 4. The assembly of claim 3, wherein the second sealingsurface is expandable to a greater diameter than the first sealingsurface.
 5. The assembly of claim 4, wherein the second sealing surfaceincludes a proximal cone portion and a distal cone portion.
 6. Theassembly of claim 5, wherein the proximal cone portion and the distalcone portion, when in expanded configurations, each form an angle withrespect to a longitudinal axis of the tube, and wherein the angle formedby the proximal cone portion is different from the angle formed by thedistal cone portion.
 7. The assembly of claim 5, wherein the proximalcone portion and the distal cone portion, when in expandedconfigurations, each form an angle with respect to a longitudinal axisof the tube, and wherein the angle formed by the proximal cone portionis less steep than the angle formed by the distal cone portion.
 8. Theassembly of claim 5, wherein the proximal cone portion of the secondsealing surface, when in an expanded configuration, forms an angleranging between approximately 10 degrees and approximately 20 degreeswith respect to a longitudinal axis of the tube.
 9. The assembly ofclaim 8, wherein the proximal cone portion of the second sealingsurface, when in an expanded configuration, forms an angle ofapproximately 15 degrees with respect to a longitudinal axis of thetube.
 10. The assembly of claim 5, wherein the distal cone portion ofthe second sealing surface, when in an expanded configuration, forms anangle ranging between approximately 20 degrees and approximately 45degrees with respect to a longitudinal axis of the tube.
 11. Theassembly of claim 10, wherein the distal cone portion of the secondsealing surface, when in an expanded configuration, forms an angle ofapproximately 30 degrees with respect to a longitudinal axis of thetube.
 12. The assembly of claim 3, wherein the distal sealing surface isadjacent a distal end of the tube.
 13. The assembly of claim 12, whereinthe distal sealing surface is attached to the distal portion of the tubeby two waist portions, and wherein at least a distal waist portion isinverted.
 14. The assembly of claim 1, further comprising a kinkresistant coil surrounding the tube.
 15. The assembly of claim 1,further comprising a support collar for supporting a proximal open endof the tube.
 16. The assembly of claim 14, further comprising anencapsulation layer encapsulating the tube and kink resistant coil. 17.The assembly of claim 16, further comprising an encapsulation layerencapsulating the tube and support collar.
 18. The assembly of claim 1,wherein the proximal end of the tube is formed at an angle and includesa reverse bevel portion.
 19. The assembly of claim 18, wherein thereverse bevel portion forms an angle ranging between approximately 30degees and approximately 60 degrees with respect to a longitudinal axisof the evacuation lumen.
 20. The assembly of claim 14, furthercomprising at least one marker band adjacent at least one end of thecoil.
 21. The assembly of claim 20, further comprising a second, shortercoil positioned between the at least one marker band and a supportcollar supporting a proximal end of the tube.
 22. The assembly of claim20, further comprising an inflation port extending through the at leastone marker band and through the tube to provide fluid communicationbetween at least one of the sealing surfaces and the inflation lumen.23. The assembly of claim 22, wherein the inflation port includes afirst portion having a first diameter and a second portion having asecond diameter, the first diameter being larger than the seconddiameter.
 24. An evacuation sheath assembly comprising: an elongatedtube defining an evacuation lumen having proximal and distal ends; and adistal sealing surface configured to form a seal with a blood vessel,the distal sealing surface including a proximal cone portion and adistal cone portion, wherein at least one of the proximal and distalcone portions, when in an expanded configuration, forms an angle withrespect to a longitudinal axis of the elongated tube.
 25. The evacuationsheath assembly of claim 24, wherein the proximal cone portion and thedistal cone portion, when in expanded configurations, each form an anglewith respect to a longitudinal axis of the tube, and wherein the angleformed by the proximal cone portion is different from the angle formedby the distal cone portion.
 26. The evacuation sheath assembly of claim24, wherein the proximal cone portion and the distal cone portion, whenin expanded configurations, each form an angle with respect to alongitudinal axis of the tube, and wherein the angle formed by theproximal cone portion is less steep than the angle formed by the distalcone portion.
 27. The evacuation sheath assembly of claim 24, whereinthe proximal cone portion, when in an expanded configuration, forms anangle ranging between approximately 10 degrees and approximately 20degrees with respect to a longitudinal axis of the tube.
 28. Theevacuation sheath assembly of claim 27, wherein the proximal coneportion, when in an expanded configuration, forms an angle ofapproximately 15 degrees with respect to a longitudinal axis of theevacuation lumen.
 29. The evacuation sheath assembly of claim 24,wherein the distal cone portion, when in an expanded configuration,forms an angle ranging between approximately 20 degrees andapproximately 45 degrees with respect to a longitudinal axis of thetube.
 30. The evacuation sheath assembly of claim 29, wherein the distalcone portion, when in an expanded configuration, forms an angle ofapproximately 30 degrees with respect to a longitudinal axis of theevacuation lumen.
 31. The evacuation sheath assembly of claim 24,wherein at least one of the ends of the lumen is formed at an angle. 32.The evacuation sheath assembly of claim 24, further comprising aproximal sealing surface at a proximal end of the tube configured toform a seal with a catheter.
 33. The evacuation sheath assembly of claim32, wherein the proximal sealing surface includes an inflatable balloon.34. The evacuation sheath assembly of claim 24, wherein the distalsealing surface includes an inflatable balloon.
 35. The evacuationsheath assembly of claim 32, wherein the proximal and distal sealingsurfaces include inflatable balloons, and wherein the distal balloon islarger than the proximal balloon.
 36. The evacuation sheath assembly ofclaim 24, further comprising a proximal shaft portion attached to aproximal end of the elongate tube.
 37. The evacuation sheath assembly ofclaim 24, further comprising a flexible tip on a distal end of theassembly.
 38. The evacuation sheath assembly of claim 37, wherein theflexible tip is formed by a portion of the distal sealing surface. 39.The evacuation sheath assembly of claim 24, wherein a proximal end ofthe evacuation lumen is formed at an angle.
 40. The evacuation sheathassembly of claim 24, further comprising at least one marker bandadjacent at least one of said proximal and distal ends of saidevacuation lumen.
 41. The evacuation assembly of claim 40, furthercomprising an inflation port extending through the at least one markerband.
 42. The evacuation assembly of claim 41, wherein the inflationport includes a first portion having a first diameter and a secondportion having a second diameter, wherein the first diameter is largerthan the second diameter.
 43. An evacuation sheath assembly comprising:an elongated tube defining an evacuation lumen having open proximal anddistal ends and an inflation lumen having an open proximal end and aclosed distal end, wherein the proximal end of the evacuation lumen isangled and includes a reverse bevel portion; and a first sealing regionon a proximal portion of the evacuation lumen and a second sealingregion on a distal portion of the evacuation lumen, wherein at least oneof the first and second sealing regions is in fluid communication withthe inflation lumen.
 44. The evacuation sheath assembly of claim 43,wherein the first sealing region is expandable to a first diameter andthe second sealing region is expandable to a second diameter differentthan the first diameter.
 45. An evacuation sheath assembly, comprising:an elongated tube defining an evacuation lumen having open proximal anddistal ends and an inflation lumen having an open proximal end and aclosed distal end; and first and second sealing surfaces on the tube;wherein the open proximal end of the evacuation lumen is angled andincludes a structure to reinforce the proximal opening of the elongatedtube.
 46. The evacuation sheath assembly of claim 45, wherein thestructure to reinforce the proximal opening of the tube is a supportcollar.
 47. The evacuation sheath assembly of claim 36, wherein thesupport collar includes a cylindrical portion positioned about theproximal open end of the tube.
 48. The evacuation sheath assembly ofclaim 46, wherein the support collar further includes a tab portionextending proximally from the cylindrical portion in a directionparallel to a longitudinal axis of the tube.
 49. The evacuation sheathassembly of claim 46, further comprising an encapsulation layerencapsulating the tube and the support collar.
 50. The evacuation sheathassembly of claim 46, wherein the support collar is formed of a metallicmaterial.
 51. The evacuation sheath assembly of claim 49, wherein theencapsulation layer is formed of polyurethane.
 52. The evacuation sheathassembly of claim 49, wherein the support collar further includes aplurality of windows to promote adhesion of the encapsulation layer tothe support collar.
 53. The evacuation sheath assembly of claim 45,wherein the tube includes a third lumen.
 54. The evacuation sheathassembly of claim 53, wherein the second and third lumens are positionedadjacent to one another.
 55. The evacuation sheath assembly of claim 53,wherein both the second lumen and the third lumen are smaller indiameter than the first lumen.
 56. The evacuation sheath assembly ofclaim 45, wherein the first and second sealing members are balloons. 57.The evacuation sheath assembly of claim 45, wherein the first and secondsealing members are elastomeric.
 58. The evacuation sheath assembly ofclaim 45, wherein the first sealing member is located on a proximalportion of the elongated tube and the second sealing member is locatedon a distal portion of the elongated tube.
 59. An evacuation sheathassembly, comprising: an elongated tube defining an evacuation lumenhaving open proximal and distal ends and an inflation lumen having anopen proximal end and a closed distal end; a kink resistant coilsurrounding the elongated tube; at least one marker band adjacent atleast one end of the kink resistant coil; and at least one inflatablesealing surface in fluid communication with the inflation lumen via aninflation port passing through the at least one marker band.
 60. Theevacuation sheath assembly of claim 59, further comprising anencapsulation layer encapsulating the kink resistant coil and elongatedtube.
 61. The evacuation sheath assembly of claim 59, wherein theinflation port includes a first portion having a first diameter and asecond portion having a second diameter, wherein the first diameter islarger than the second diameter.
 62. The evacuation sheath assembly ofclaim 60, wherein the inflation port includes a first portion extendingthrough the marker band and having a first diameter.
 63. The evacuationsheath assembly of claim 62, wherein the inflation port includes asecond portion extending through the encapsulation layer and having asecond diameter.
 64. The evacuation sheath assembly of claim 63, whereinthe first diameter is larger than the second diameter.
 65. An evacuationsheath assembly, comprising: an elongated tube defining an evacuationlumen having open proximal and distal ends and an inflation lumen havingan open proximal end and a closed distal end; and proximal and distalsealing surfaces in fluid communication with the inflation lumen;wherein the distal sealing surface extends distally beyond the distalend of the evacuation lumen.
 66. The evacuation sheath assembly of claim65, wherein a waist portion connecting the balloon to the tube isinverted.
 67. A combination for isolating fluid communication between ablood vessel and a catheter, comprising: a catheter having a lumen; anevacuation sheath assembly configured to move within the lumen of thecatheter and having an evacuation lumen and first and second sealingmembers; and a three-arm adaptor having a first arm for receiving aguide wire, a second arm for receiving the evacuation sheath assembly,and a third arm for connection to an evacuation means, wherein the thirdarm is spaced distally from the first and second arms.
 68. Thecombination of claim 67, wherein the evacuation means includes a meansfor creating a vacuum.
 69. The combination of claim 67, wherein theevacuation means includes an evacuation syringe.
 70. The combination ofclaim 67, wherein the proximal end of the evacuation lumen includesmeans for preventing devices from hanging up on the evacuation lumen.71. The combination of claim 70, wherein the means for preventingdevices from hanging up on the evacuation lumen includes an angledproximal end of the evacuation lumen.
 72. The combination of claim 71,wherein the means for preventing devices from hanging up on theevacuation lumen further includes a reverse beveled portion on theproximal end of the evacuation lumen.
 73. The combination of claim 67,wherein the first sealing member includes a proximal portion of theevacuation sheath assembly configured to seal against the lumen of thecatheter.
 74. The combination of claim 67, wherein the second sealingmember is located on a distal portion of the evacuation sheath assembly.75. The combination of claim 67, wherein the first and second sealingmembers include expandable surfaces.
 76. The combination of claim 67,wherein the second sealing member is configured to create a seal betweenthe evacuation sheath assembly and the blood vessel.
 77. The combinationof claim 75, wherein a distal end of the evacuation lumen isperpendicular to a longitudinal axis of the evacuation lumen.
 78. Thecombination of claim 77, wherein the second sealing member is adjacentthe distal end of the evacuation lumen.
 79. The combination of claim 78,wherein the second sealing member extends distally beyond the distal endof the evacuation lumen.
 80. The combination of claim 79, wherein thesecond sealing member includes an inverted waist portion attaching thesecond sealing member to an outer surface of the evacuation lumen. 81.The combination of claim 80, wherein the expandable surfaces areinflatable balloons.
 82. The combination of claim 81, wherein the secondsealing member includes proximal and distal cone portions.
 83. Thecombination of claim 82, wherein the proximal cone portion and thedistal cone portion, when in expanded configurations, each form an anglewith respect to a longitudinal axis of the tube, and wherein the angleformed by the proximal cone portion is different from the angle formedby the distal cone portion.
 84. The combination of claim 82, wherein theproximal cone portion and the distal cone portion, when in expandedconfigurations, each form an angle with respect to a longitudinal axisof the tube, and wherein the angle formed by the proximal cone portionis less steep than the angle formed by the distal cone portion.
 85. Thecombination of claim 82, wherein the proximal cone portion, when in anexpanded configuration, forms an angle ranging between approximately 10degrees and approximately 20 degrees with respect to a longitudinal axisof the tube.
 86. The combination of claim 85, wherein the proximal coneportion, when in an expanded configuration, forms an angle of about 15degrees with respect to a longitudinal axis of the evacuation lumen. 87.The combination of claim 82, wherein the distal cone portion, when in anexpanded configuration, forms an angle ranging between approximately 20degrees and approximately 45 degrees with respect to a longitudinal axisof the tube.
 88. The combination of claim 87, wherein the distal coneportion, when in an expanded configuration, forms an angle of about 30degrees with respect to a longitudinal axis of the evacuation lumen.